High-viscosity anti-digestion starch-chitosan complex coacervate as well as preparation method and application thereof

Abstract

The invention discloses a high-viscosity anti-digestion starch-chitosan complex coacervate product as well as a preparation method and application thereof, and relates to the technical field of food processing. The content of resistant starch RS in the high-viscosity anti-digestion starch-chitosan complex coacervate product disclosed by the invention is 25.75%-37.56%; the final viscosity value of the high-viscosity anti-digestion starch-chitosan complex coacervate product is 2389 cP to 3439 cP; wherein the final viscosity value is a viscosity value obtained by heating the slurry from 50 DEG C to 95 DEG C, then cooling the slurry to 50 DEG C, carrying out a viscosity test, and testing the slurry in 13th min after the start of the test in the viscosity test process. According to the method, the content of resistant starch RS in the high-viscosity anti-digestion starch-chitosan complex coacervate product can be effectively increased, and meanwhile, the final viscosity value of the high-viscosity anti-digestion starch-chitosan complex coacervate product can be effectively increased.

Description

Technical Field

[0001] This invention belongs to the field of resistant starch technology, specifically relating to a high-viscosity resistant starch-chitosan complex coagulate, its preparation method, and its application. Background Technology

[0002] In recent years, adding other components to starch to increase the content of resistant starch (RS) has attracted much attention from researchers. However, this method usually leads to a decrease in the viscosity of the system (referring to the system generated after modifying starch with other components). To address this, this application proposes a high-viscosity resistant starch-chitosan complex coagulate product with high viscosity and high resistant starch (RS) content, as well as its preparation method and application. Summary of the Invention

[0003] The present invention aims to provide a high-viscosity, digestible starch-chitosan complex coagulate, its preparation method, and its application.

[0004] To achieve the above object, the technical solution adopted by the present invention is: A high-viscosity resistant starch-chitosan complex coagulate, wherein the resistant starch (RS) content in the high-viscosity resistant starch-chitosan complex coagulate product is 25.75% to 37.56%; the final viscosity value of the high-viscosity resistant starch-chitosan complex coagulate product is 2389 cP to 3439 cP; wherein, the final viscosity value refers to the viscosity value obtained by heating the slurry from 50°C to 95°C and then cooling it back to 50°C during the viscosity test, and the viscosity test is performed on the slurry at 13 minutes after the start of the test.

[0005] A method for preparing a high-viscosity resistant starch-chitosan complex coagulate, wherein the high-viscosity resistant starch-chitosan complex coagulate is the aforementioned high-viscosity resistant starch-chitosan complex coagulate, and the method for preparing the high-viscosity resistant starch-chitosan complex coagulate includes the following steps: S1. Completely dissolve chitosan powder in acetic acid solution to obtain chitosan acetic acid solution; S2. Under stirring conditions, corn starch is added to the chitosan acetate solution to obtain the initial product of corn starch-chitosan liquid complex aggregate; S3. The initial product of corn starch-chitosan liquid complex coagulate is annealed by stirring at 30℃~60℃ for 6h~48h, then freeze-dried, then ground into powder, and passed through an 80~100 mesh sieve to obtain a high viscosity resistant starch-chitosan complex coagulate product.

[0006] Preferably, in step S1, the acetic acid solution is obtained by uniformly mixing acetic acid and ultrapure water; in the acetic acid solution, the mass concentration of acetic acid is 1%, and the mass ratio of chitosan to acetic acid is 1-5:0.5-2.

[0007] Preferably, the specific steps of step S1 are as follows: dissolve chitosan powder in acetic acid solution, and stir at 30℃~60℃ with continuous stirring until the chitosan is completely dissolved to obtain chitosan acetic acid solution; wherein, during the continuous stirring process, the stirring speed is 160rpm~320rpm.

[0008] Preferably, the specific steps of step S2 are as follows: under stirring conditions, corn starch is added to the chitosan acetate solution, and then, under the condition of 30-60°C, stirring is continued for 0.5h-2h to obtain the initial product of corn starch-chitosan liquid complex aggregate; wherein, the stirring speed is 160rpm-320rpm.

[0009] Preferably, in step S2, the mass ratio of chitosan to corn starch is 1-5:10-20.

[0010] Preferably, in step S3, the stirring speed is 160 rpm to 320 rpm.

[0011] Preferably, in step S3, the freeze-drying temperature is -50℃ to -80℃.

[0012] Applications of the aforementioned high-viscosity, resistant-to-digest starch-chitosan complex coagulates in the food industry.

[0013] A hydrogel prepared using a high-viscosity, digestible starch-chitosan complex aggregate includes the following steps: A high-viscosity resistant starch-chitosan complex coagulate was mixed with water at a mass-to-volume ratio of (0.5–2) g:(5–20) ml. The mixture was stirred continuously at 30°C–60°C for 10–60 min to form a suspension. The suspension was then heated at 90°C–100°C for 20–60 min and cooled for 1–6 h to obtain a hydrogel. The high-viscosity resistant starch-chitosan complex coagulate is the same as described above.

[0014] Compared with the prior art, the present invention has the following beneficial effects: In the preparation of the high-viscosity resistant starch-chitosan complex coagulate product, the amino / hydroxyl groups of chitosan form hydrogen bonds with the hydroxyl groups of corn starch. Furthermore, the nonpolar regions of both form a hydrophobic attraction, allowing chitosan to effectively spread on the surface of corn starch granules before freeze-drying. After freeze-drying, this chitosan forms a chitosan coating layer, effectively encapsulating the corn starch granules. During digestion testing, the chitosan coating layer effectively prevents digestive enzymes (α-amylase and glucoamylase) from contacting the corn starch granules, thus reducing enzymatic hydrolysis and increasing the RS content. However, the chitosan coating layer also hinders the movement of corn starch granules within the system, leading to an increase in the viscosity of the high-viscosity resistant starch-chitosan complex coagulate product. The experimental results show that the final viscosity of the high-viscosity resistant starch-chitosan complex prepared in Example 1 of this application is as high as 3439 cP; moreover, the content of rapidly digestible starch (RDS) in the high-viscosity resistant starch-chitosan complex product can be as low as 53.66±1.02%, the content of slowly digestible starch (SDS) can be as low as 8.78±1.55%, and the content of resistant starch (RS) can be increased to 37.56±1.55%.

[0015] Furthermore, the raw materials used in this application, such as corn starch and chitosan, are widely available and inexpensive; moreover, the method for producing high-viscosity, resistant-digesting starch-chitosan complex coagulants is easy to industrialize and has extremely high production and application value. Attached Figure Description

[0016] Figure 1 Viscosity analysis results of corn starch, the high-viscosity resistant starch-chitosan complex aggregate product prepared in Example 1, and the comparative samples prepared in Comparative Examples 1, 4, 5, 6, 13, and 14. Figure 2 Viscosity analysis results of corn starch, the high-viscosity resistant starch-chitosan complex aggregate product prepared in Example 2, and the comparative samples prepared in Comparative Examples 3, 7, 9, 11, 15 and 16. Figure 3 Viscosity analysis results of corn starch, the high-viscosity resistant starch-chitosan complex aggregate product prepared in Example 3, and the comparative samples prepared in Comparative Examples 2, 8, 10, 12, 17 and 18. Figure 4 Fourier transform infrared spectroscopy analysis results of corn starch, the high viscosity resistant starch-chitosan complex aggregate product prepared in Example 1, and the comparative samples prepared in Comparative Examples 4, 5 and 6. Figure 5 Fluorescence microscopy analysis results of corn starch, the high-viscosity resistant starch-chitosan complex aggregate product prepared in Example 1, and the comparative samples prepared in Comparative Examples 4, 5, and 6; Figure 6 Scanning electron microscopy analysis results of corn starch, the high viscosity resistant starch-chitosan complex aggregate product prepared in Example 1, and the comparative samples prepared in Comparative Examples 4, 5, and 6; Figure 7 The scanning electron microscope analysis results are for the comparative samples prepared in Comparative Examples 13 and 14. Figure 8 The results of the spoon tilt test are shown for the complex aggregate hydrogel prepared in Application Example 1 and the control hydrogel prepared in Control Example 1. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: This embodiment provides a high-viscosity, digestible starch-chitosan complex coagulate, which is prepared by the following method for preparing high-viscosity, digestible starch-chitosan complex coagulates, specifically including the following steps: S1. Dissolve 3 g of chitosan powder in 87 g of acetic acid solution, and heat in a water bath at 40 °C with continuous stirring for 6 h until the chitosan is completely dissolved to obtain a chitosan acetic acid solution; wherein, the acetic acid solution is obtained by uniformly mixing 86 g of ultrapure water and 1 g of acetic acid; and during the continuous stirring process, the stirring speed is 160 rpm. S2. While continuing to stir, add 10 g of corn starch to the chitosan acetate solution obtained in step S1, and then continue stirring at 40 °C for 0.5 h to obtain the initial product of corn starch-chitosan liquid complex aggregate; wherein, in step S2, the stirring speed is also 160 rpm. S3. The corn starch-chitosan liquid complex coagulant obtained in step S2 is annealed by stirring at 40°C for 24 hours at a stirring speed of 160 rpm. Then, it is freeze-dried at a temperature of -60°C. After that, it is ground into powder and passed through an 80-mesh sieve to obtain a high-viscosity, digestible starch-chitosan complex coagulant product.

[0019] Example 2: The difference between this embodiment and Embodiment 1 is that in step S1, 1 g of chitosan powder is dissolved in 89 g of acetic acid solution, which is obtained by uniformly mixing 88 g of ultrapure water and 1 g of acetic acid.

[0020] Example 3: The difference between this embodiment and Embodiment 1 is that in step S1, 2 g of chitosan powder is dissolved in 88 g of acetic acid solution, which is obtained by uniformly mixing 87 g of ultrapure water and 1 g of acetic acid.

[0021] Comparative Example 1: Comparative Example 1: The chitosan-corn starch mixture was prepared by the following steps: 3 g of chitosan powder and 10 g of corn starch were mixed and ground into powder, and then passed through an 80-mesh sieve to obtain the chitosan-corn starch mixture, which was used as a control sample.

[0022] Comparative Example 2: The difference between Comparative Example 2 and Comparative Example 1 is that 2 g of chitosan powder and 10 g of corn starch were mixed and ground into powder, which was then passed through an 80-mesh sieve to obtain a chitosan-corn starch mixture, which served as the control sample.

[0023] Comparative Example 3: The difference between Comparative Example 3 and Comparative Example 1 is that 1 g of chitosan powder and 10 g of corn starch were mixed and ground into powder, which was then passed through an 80-mesh sieve to obtain a chitosan-corn starch mixture, which served as the control sample.

[0024] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that in step S1, chitosan powder is replaced with ε-polylysine powder, and acetic acid solution is replaced with ultrapure water, that is, 3 g of ε-polylysine powder is dissolved in 87 g of ultrapure water.

[0025] Comparative Example 5: The difference between Comparative Example 5 and Example 1 is that in step S1, chitosan powder is replaced with type A gelatin powder, and acetic acid solution is replaced with ultrapure water, that is, 3 g of type A gelatin powder is dissolved in 87 g of ultrapure water.

[0026] Comparative Example 6: The difference between Comparative Example 6 and Example 1 is that in step S1, chitosan powder is replaced with chitosan oligosaccharide powder, and acetic acid solution is replaced with ultrapure water, that is, 3 g of chitosan oligosaccharide powder is dissolved in 87 g of ultrapure water.

[0027] Comparative Example 7: The difference between Comparative Example 7 and Comparative Example 4 is that in step S1, 1g of ε-polylysine powder was dissolved in 89g of ultrapure water.

[0028] Comparative Example 8: The difference between Comparative Example 8 and Comparative Example 4 is that in step S1, 2g of ε-polylysine powder was dissolved in 88g of ultrapure water.

[0029] Comparative Example 9: The difference between Comparative Example 9 and Comparative Example 5 is that in step S1, 1g of type A gelatin powder is dissolved in 89g of ultrapure water.

[0030] Comparative Example 10: The difference between Comparative Example 10 and Comparative Example 5 is that in step S1, 2 g of type A gelatin powder is dissolved in 88 g of ultrapure water.

[0031] Comparative Example 11: The difference between Comparative Example 11 and Comparative Example 6 is that in step S1, 1 g of chitosan oligosaccharide powder was dissolved in 89 g of ultrapure water.

[0032] Comparative Example 12: The difference between Comparative Example 12 and Comparative Example 6 is that in step S1, 2 g of chitosan oligosaccharide powder was dissolved in 88 g of ultrapure water.

[0033] Comparative Example 13: The difference between Comparative Example 13 and Example 1 is that the annealing and freeze-drying treatment in step S3 is replaced by drying the corn starch-chitosan liquid complex aggregate in an oven at 110 ℃ for 1.5 h. Specifically, step S3 in Comparative Example 13 includes the following steps: the corn starch-chitosan liquid complex aggregate obtained in step S2 is dried in an oven at 110 ℃ for 1.5 h, then ground into powder and passed through an 80-mesh sieve to obtain the comparative sample.

[0034] Comparative Example 14: The difference between Comparative Example 14 and Example 1 is that the annealing step in step S3 is omitted. Specifically, step S3 in Comparative Example 14 includes the following steps: the corn starch-chitosan liquid complex aggregate obtained in step S2 is freeze-dried at a temperature of -60°C, and then ground into powder and passed through an 80-mesh sieve to obtain the comparative sample.

[0035] Comparative Example 15: The difference between Comparative Example 15 and Example 2 is that the annealing and freeze-drying process in step S3 is replaced by drying the corn starch-chitosan liquid complex aggregate in an oven at 110°C for 1.5 h.

[0036] Comparative Example 16: The difference between Comparative Example 16 and Example 2 is that the annealing process in step S3 is omitted.

[0037] Comparative Example 17: The difference between Comparative Example 17 and Example 3 is that the annealing and freeze-drying processes in step S3 are replaced by drying the composite in an oven at 110 °C for 1.5 h.

[0038] Comparative Example 18: The difference between Comparative Example 18 and Example 3 is that the annealing process in step S3 is omitted.

[0039] test: The high-viscosity, digestible starch-chitosan complex aggregates prepared in Examples 1 to 3, and the comparative samples prepared in Comparative Examples 1 to 18, were tested using the following methods: Test Method 1 – Digestion Test Method: In this application, three parallel test samples were prepared for the high viscosity resistant starch-chitosan complex coagulate products prepared in Examples 1 to 3 and the comparative samples prepared in Comparative Examples 1 to 18, respectively. The digestion test methods were then used to test them, as follows; 40 mg of the test sample was added to 35 mL of sodium acetate buffer solution with a pH of 5.2 and stirred at 100 °C for 30 min to gelatinize the sample at a stirring speed of 150 rpm. The gelatinized sample was then immediately placed in a 37 °C water bath and allowed to stand for 10 min. Next, 10 mL of saccharifying enzyme solution and 10 mL of α-amylase solution were added to the water bath. The concentration of saccharifying enzyme in the saccharifying enzyme solution was 30 U / mL, and the concentration of α-amylase in the α-amylase solution was 290 U / mL. The liquid in the water bath was then stirred and timed at 37 °C at a stirring speed of 150 rpm. 0.25 mg of the sample was collected at 0 min, 20 min, and 120 min. The liquid in the uL water bath was then immediately measured using a biosensor to determine the glucose concentration in the extracted liquid. The saccharifying enzyme solution was obtained by uniformly mixing saccharifying enzyme powder and a sodium acetate buffer solution at pH 5.2, while the α-amylase solution was obtained by uniformly mixing α-amylase powder and a sodium acetate buffer solution at pH 5.2. The test samples in this application refer to the high-viscosity, digestible starch-chitosan complex coagulated products prepared in Examples 1 to 3 and the comparative samples prepared in Comparative Examples 1 to 18.

[0040] From a nutritional perspective, starch is generally classified into three categories: rapidly digestible starch (RDS), which is starch that is rapidly digested and absorbed in the small intestine (quantitatively measured as the amount of glucose produced by enzymatic hydrolysis within 20 minutes); slowly digestible starch (SDS), which is starch that is completely digested and absorbed in the small intestine, but at a slower rate (quantitatively measured as the amount of glucose produced by enzymatic hydrolysis within 20-120 minutes); and starch that cannot be digested and absorbed by the small intestine (quantitatively measured as starch that remains undigested even after 120 minutes). Therefore, this application calculates the percentage content X of rapidly digestible starch (RDS) in the test sample by calculating the amount of glucose released within 20 minutes of enzymatic digestion. RDS The percentage content X of slowly digested starch (SDS) in the test sample was obtained by calculating the amount of glucose released during enzymatic digestion time ranging from 20 min to 120 min. SDS The percentage of resistant starch (RS) in the test sample was obtained by calculating the portion that remained unhydrolyzed after 120 min of enzymatic digestion. RS The percentage of rapidly digestible starch in the test sample, X, is among the parameters. RDS The percentage of slowly digestible starch in the test sample X SDS The percentage content of resistant starch in the test sample X RS The calculation formulas are shown in equations (1) to (3) respectively: XRDS = ( G 20 - FG ) × 0.9 / TS × 100% (1) X SDS = ( G 120 - G 20 ) × 0.9 / TS × 100% (2) X RS =1- X RDS - X SDS (3) In equations (1) to (3), G 20 FG represents the glucose content (mg) in the liquid taken from the water bath after 20 min of enzymatic digestion; G represents the glucose content (mg) in the liquid taken from the water bath after 0 min of enzymatic digestion. 120 The glucose content (mg) in the liquid taken from the water bath was measured after 120 min of enzymatic digestion; TS represents the corn starch content (mg) in the test sample; in this application, the glucose content (mg) is obtained by multiplying the glucose concentration in the liquid by the volume of the test liquid measured by a biosensor.

[0041] In this application, three parallel test samples were prepared from the high-viscosity, digestible starch-chitosan complex coagulants prepared in Examples 1 to 3 and the comparative samples prepared in Comparative Examples 1 to 18, respectively. These samples were then tested using a digestion test method to obtain three percentage content X values. RDS Three percentage contents X SDS And three percentage content X RS ; X the three percentage contents RDS Data analysis was performed using IBM SPSS Statistics 22 software, and the results are shown in Table 1. The three percentage contents X... SDS Data analysis was performed using SPSS software, and the results are shown in Table 1. The three percentage contents X... RS Data analysis was performed using SPSS software, and the results are shown in Table 1.

[0042] Test Method 2 – Viscosity Test Method: This application uses a rapid viscosity analyzer to determine the viscosity of the test sample. Specifically, 2.5 g of the test sample and 25.5 g of ultrapure water are mixed evenly in an RVA-specific aluminum box to obtain a slurry. The slurry is then tested. In the first 10 seconds before the test begins, the slurry is stirred with a paddle at a speed of 960 rpm. After 10 seconds, the paddle speed is reduced to 160 rpm. The slurry is heated from 50°C to 95°C and then cooled to 50°C for viscosity determination. Timing is performed during the slurry test. The viscosity value obtained at 13 minutes after the start of the test is the final viscosity value.

[0043] Test Method 3 – Infrared Test Method: The test sample was mixed with potassium bromide at a mass ratio of 1:100, compacted into tablets, and then analyzed using a spectrometer at 500–4000 cm⁻¹. -1 The analysis is performed within the wavelength range.

[0044] Test Method 4 – Fluorescence Microscopy Test Method: Mix 0.1 g of test sample, 4.9 g of water and 10 uL of FITC solution (FITC concentration of 0.2%), stir at 25 °C for 30 min, and observe with a fluorescence microscope.

[0045] Test Method 5 – Scanning Electron Microscopy Test Method: The test samples were dispersed and fixed to a metal platform with conductive adhesive. After the metal platform was coated with a thin layer of gold, the test samples were observed under a scanning electron microscope and photographed at 1000x magnification.

[0046] Test results and analysis: (1) Digestion test results, as shown in Tables 1 to 3: Table 1

[0047] Table 2

[0048] Table 3

[0049] As can be seen from Tables 1 to 3, the highest RS content in the high viscosity resistant starch-chitosan complex coagulated products prepared in Examples 1 to 3 of this application is 37.56 ± 1.55%, and the lowest is 25.75 ± 0.59%.

[0050] Furthermore, (1) the test data of Example 1 and Comparative Example 1 in Table 1 also show that, under the condition that the mass ratio of corn starch to chitosan is 10:3, the high viscosity resistant starch-chitosan complex coagulant product prepared by the process steps described in Example 1 of this application has an RS content that is (37.56-17.65) / 17.65×100%=112.80% higher than that of the comparative product prepared by Comparative Example 1; (2) the test data of Example 1, Comparative Example 4, Comparative Example 5 and Comparative Example 6 in Table 1 also show that the RS content of the high viscosity resistant starch-chitosan complex coagulant product prepared by using chitosan and corn starch as raw materials and the process steps described in Example 1 of this application is significantly higher than that of the products prepared by using other components and corn starch as raw materials in Comparative Example 4, Comparative Example 5 and Comparative Example 6. The RS content in the comparative sample prepared by the process steps of the method described in Example 1, wherein the RS content in the high viscosity resistant starch-chitosan complex coagulant product prepared in Example 1 of this application increased by (37.56-35.54) / 35.54×100%=5.68% compared with the RS content in the comparative sample prepared in Comparative Example 5; (3) From the test data of Example 1, Comparative Example 13 and Comparative Example 14 in Table 1, it can also be seen that under the condition that the steps S1 of Example 1 and Comparative Example 13 and Comparative Example 14 are the same, and the steps S2 are also the same, using the specific process parameters described in step S3 of Example 1 of this application (mainly reflected in the annealing process step and the freeze-drying process step), compared with Comparative Example 13 which does not use the annealing process step and freeze-drying process step described in Example 1 but uses 110 The method of drying at ℃ and the omission of annealing treatment in Comparative Example 14 (i.e., not using the annealing treatment process steps described in Example 1) and the use of only freeze-drying process steps resulted in a significantly higher RS ​​content in the high viscosity resistant starch-chitosan complex coagulate product prepared in Example 1 of this application compared to the comparative samples prepared in Comparative Examples 13 and 14. Specifically, the RS content in the high viscosity resistant starch-chitosan complex coagulate product prepared in Example 1 of this application increased by 56.11% and 18.04% compared to the comparative samples prepared in Comparative Examples 13 and 14, respectively.

[0051] Similarly, as can be seen from Table 2: 1) Under the condition that the mass ratio of corn starch to chitosan is 10:1, the high-viscosity resistant starch-chitosan complex coagulant product prepared by the process steps described in Example 2 of this application has a 76.25% higher RS ​​content than the comparative product prepared by Comparative Example 3; 2) The high-viscosity resistant starch-chitosan complex coagulant product prepared by using chitosan and corn starch as raw materials and the process steps described in Example 2 of this application has a lower RS ​​content than the product prepared by using other components and corn starch as raw materials in Comparative Example 11 and the process steps described in Example 2 of this application. The RS content in the comparative sample increased by 35.53%; 3) Under the same conditions as step S1 and step S2, using the specific process parameters described in step S3 of Example 1 of this application (mainly reflected in the annealing process and freeze-drying process), compared with the drying method of 110℃ in Comparative Example 15 and the freeze-drying process setting in Comparative Example 16, the RS content in the high viscosity resistant starch-chitosan complex coagulant product prepared in Example 2 of this application increased by 54.75% and 5.58% respectively compared with the RS content in the comparative samples prepared in Comparative Example 15 and Comparative Example 16.

[0052] Similarly, as can be seen from Table 3: 1) Under the condition that the mass ratio of corn starch to chitosan is 10:2, the high viscosity resistant starch-chitosan complex coagulant product prepared by the process steps described in Example 3 of this application has an RS content that is 115.23% higher than that of the comparative product prepared by Comparative Example 2; 2) The high viscosity resistant starch-chitosan complex coagulant product prepared by using chitosan and corn starch as raw materials and the process steps described in Example 3 of this application has an RS content that is lower than that of the product prepared by using other components and corn starch as raw materials and the process steps described in Example 3 of this application. The RS content in the comparative sample increased by 9.12%; 3) Under the same conditions as step S1 and step S2, using the specific process parameters described in step S3 of Example 1 of this application (mainly reflected in the annealing process and freeze-drying process), compared with the drying method of 110℃ in Comparative Example 17 and the freeze-drying process setting of Comparative Example 18, the RS content in the high viscosity resistant starch-chitosan complex coagulant product prepared in Example 3 of this application increased by 77.61% and 25.23% respectively compared with the RS content in the comparative samples prepared in Comparative Example 17 and Comparative Example 18.

[0053] (2) Viscosity test results are as follows Figures 1 to 3 ; The high-viscosity, digestible starch-chitosan complex aggregates prepared in Examples 1 to 3 of this application have final viscosity values ​​of 3439 cP, 2389 cP, and 3013 cP, respectively.

[0054] In addition, 1) from Figure 1 The test data from Example 1 and Comparative Example 1 also show that, under the condition that the mass ratio of corn starch to chitosan is 10:3, the final viscosity value (3439 cP) of the high-viscosity resistant starch-chitosan complex aggregate product prepared by the process steps described in this application is (4526-3439) / 4526=24.02% lower than the final viscosity value (4526 cP) of the comparative product prepared by Comparative Example 1. However, as shown in Table 1, the RS content in the comparative product prepared by Comparative Example 1 is lower, only 17.65 ± 1.02%. Obviously, the RS content in the comparative sample prepared by Comparative Example 1 is lower (17.65 ± 1.02%), and the final viscosity value is higher (4526 cP). 2) From Figure 1 The test data from Examples 1, 4, 5, and 6 also show that the viscosity of the high-viscosity resistant starch-chitosan complex aggregate product prepared using chitosan and corn starch as raw materials and the process steps described in Example 1 of this application is significantly higher than the viscosity of the comparative samples prepared using other components and corn starch as raw materials in Examples 4, 5, and 6. Specifically, the viscosity of the high-viscosity resistant starch-chitosan complex aggregate product prepared in Example 1 (3439 cP) is (3439-874) / 874×100%=293.48% higher than the final viscosity of the comparative sample prepared in Example 4 (874 cP). Furthermore, as shown in Table 1, the RS content in the comparative product prepared in Example 4 is 34.19±1.01%. Obviously, the RS content in the comparative sample prepared in Example 4 is higher (34.19±1.01%), and the final viscosity value is lower (874 cP). 3) From Figure 1The test data from Examples 1, 13, and 14 also show that, under the conditions that steps S1 and S2 are the same in Examples 1, 13, and 14, and using the specific process parameters described in step S3 of Example 1 (mainly reflected in the annealing and freeze-drying processes), compared to Comparative Example 13 which does not use the annealing and freeze-drying processes described in Example 1 but instead uses a 110°C drying method, and Comparative Example 14 which omits the annealing process (i.e., does not use the annealing process described in Example 1 but only uses the freeze-drying process), the viscosity value (3439 cP) of the high-viscosity, digestible starch-chitosan complex aggregate product prepared in Example 1 is significantly higher than the viscosity value (1329 cP) of the comparative sample prepared in Comparative Example 13 and the viscosity value (3255 cP) of the comparative sample prepared in Comparative Example 14. cP), wherein the viscosity value of the high viscosity resistant starch-chitosan complex aggregate product prepared in Example 1 of this application is increased by (3439-1329) / 1329×100%=158.77% and (3439-3255) / 3255×100%=5.65% respectively compared with the final viscosity values ​​of the comparative samples prepared in Comparative Example 13 and Comparative Example 14.

[0055] Similarly, from Figure 2 It can be seen that: 1) Under the condition that the mass ratio of corn starch and chitosan is 10:1, the final viscosity value (2389 cP) of the high viscosity resistant starch-chitosan complex aggregate product prepared by the process steps described in Example 2 of this application is reduced by (3253-2389) / 3253×100%=26.56% compared with the final viscosity value (3253 cP) of the comparative product prepared by Comparative Example 3. However, as shown in Table 2, the RS content in the comparative product prepared by Comparative Example 3 is only 14.61 ± 0.59%; obviously, the RS content in the comparative sample prepared by Comparative Example 3 is low (14.61 ± 0.59%), and the final viscosity value is high (3253 cP). 2) The final viscosity value (2389 cP) of the high-viscosity resistant starch-chitosan complex aggregate product prepared using chitosan and corn starch as raw materials and the process steps described in Example 2 of this application is (2389-1109) / 1109×100%=115.42% higher than the final viscosity value (1109 cP) of the comparative sample prepared using other components and corn starch as raw materials in Comparative Example 9. Furthermore, as shown in Table 2, the RS content in the comparative product prepared in Comparative Example 9 is relatively low, at only 17.98 ± 2.68%. Obviously, both the RS content and the final viscosity value in the comparative sample prepared in Comparative Example 9 are relatively low. 3) Under the same conditions as step S1 and step S2, using the specific process parameters described in step S3 of Example 1 of this application (mainly reflected in the annealing process and freeze-drying process), compared with the drying method of 110℃ in Comparative Example 15 and the freeze-drying process only in Comparative Example 16, the final viscosity value (2389 cP) of the high viscosity resistant starch-chitosan complex aggregate product prepared in Example 2 of this application is increased by (2389-1760) / 1760×100%=35.74% and (2389-2256) / 2256×100%=5.90% respectively compared with the final viscosity value (1760 cP) of the comparative sample prepared in Comparative Example 15 and the final viscosity value (2256 cP) of the comparative sample prepared in Comparative Example 16.

[0056] Similarly, from Figure 3 It can be seen that: 1) Under the condition that the mass ratio of corn starch and chitosan is 10:2, the final viscosity value (3013 cP) of the high viscosity resistant starch-chitosan complex aggregate product prepared by the process steps described in Example 3 of this application is reduced by (3949-3013) / 3949×100%=23.70% compared with the final viscosity value (3949 cP) of the comparative product prepared by Comparative Example 2. However, as shown in Table 3, the RS content in the comparative product prepared by Comparative Example 2 is only 15.96 ± 1.01%; 2) The final viscosity value (3013 cP) of the high-viscosity resistant starch-chitosan complex aggregate product prepared using chitosan and corn starch as raw materials and the process steps described in Example 3 of this application is increased by (3013-1005) / 1005×100%=199.80% compared with the final viscosity value (1005 cP) of the comparative sample prepared using other components and corn starch as raw materials in Comparative Example 12. 3) Under the same conditions as step S1 and step S2, using the specific process parameters described in step S3 of Example 1 of this application (mainly reflected in the annealing process and freeze-drying process), compared with the drying method of 110℃ used in Comparative Example 17 and the freeze-drying process set only in Comparative Example 18, the final viscosity value (3013 cP) of the high viscosity resistant starch-chitosan complex aggregate product prepared in Example 3 of this application is increased by (3013-1598) / 1598×100%=88.55% and (3013-2455) / 2455×100%=22.73% respectively compared with the final viscosity value (1598 cP) of the comparative sample prepared in Comparative Example 17 and the final viscosity value (2455 cP) of the comparative sample prepared in Comparative Example 18.

[0057] (3) Infrared test results, such as Figure 4 As shown; Depend on Figure 4 It can be seen that the characteristic peak of hydrogen bonding in corn starch is 3411 cm⁻¹. −1 The hydrogen bond characteristic peak of the high-viscosity, digestible starch-chitosan complex aggregate product prepared in Example 1 was 3422 cm⁻¹. −1 The comparative samples prepared in Comparative Examples 4, 5, and 6 were 3402 cm³, respectively. −1 3401cm −1 3413cm −1 ; In the preparation of the high-viscosity, digestible starch-chitosan complex aggregate product described in Example 1, the amino / hydroxyl groups of chitosan form hydrogen bonds with the hydroxyl groups of corn starch. Furthermore, the non-polar regions of both attract each other due to hydrophobic interactions. This allows the chitosan to effectively spread on the surface of corn starch particles before freeze-drying, and after freeze-drying, these chitosan particles become a chitosan coating layer, effectively encapsulating the corn starch particles. Figure 4 As can be seen, the hydrogen bond characteristic peaks in the high-viscosity resistant starch-chitosan complex coagulate product prepared in Example 1 of this application show a shift to higher wavenumbers compared to the hydrogen bond characteristic peaks in the comparative samples prepared from corn starch and Comparative Examples 4, 5, and 6. This indicates that the intermolecular hydrogen bonds formed between corn starch molecules and chitosan in the high-viscosity resistant starch-chitosan complex coagulate product prepared in Example 1 are significantly more numerous than the intermolecular hydrogen bonds formed between corn starch molecules and ε-polylysine in Comparative Example 4, between corn starch and type A gelatin in Comparative Example 5, and between corn starch and chitosan oligosaccharides in Comparative Example 6. The increased number of intermolecular hydrogen bonds between corn starch molecules and chitosan indicates that the chitosan coating layer in the high-viscosity resistant-digestible starch-chitosan complex coagulate product described in Example 1 of this application can more tightly encapsulate the corn starch particles. During digestion testing, the chitosan coating layer effectively prevents digestive enzymes (α-amylase and glucoamylase) from contacting the corn starch particles, thereby effectively reducing enzymatic hydrolysis of the corn starch particles and increasing the RS content. Furthermore, the chitosan coating layer's encapsulation of the corn starch particles hinders their movement within the system, leading to an increase in the viscosity of the high-viscosity resistant-digestible starch-chitosan complex coagulate product.

[0058] (4) Results of fluorescence microscopy tests, such as Figure 5 As shown, Figure 5 In the image, the green area represents corn starch; from Figure 5As can be seen, compared with the fluorescence microscopy test image of corn starch, the fluorescence microscopy test image of the high viscosity resistant starch-chitosan complex aggregate product prepared in Example 1 of this application shows a large area of ​​blurred regions. The main reason for the formation of these blurred regions is that the amino / hydroxyl groups of chitosan form hydrogen bonds with the hydroxyl groups of corn starch, and the non-polar regions of the two also attract each other due to hydrophobic interactions. This allows chitosan to be effectively spread on the surface of corn starch particles before freeze-drying, and after freeze-drying, these chitosans become chitosan coating layers, which effectively encapsulate the corn starch particles. In the fluorescence microscopy images of the comparative samples prepared in Examples 4, 5, and 6, no large areas of blurring were observed at the corn starch granules. This indicates that ε-polylysine, type A gelatin, and chitosan oligosaccharides in the comparative samples prepared in Examples 4, 5, and 6 only coated a small amount of corn starch. This further demonstrates that, compared to using other components and corn starch as raw materials, the corn starch in the high-viscosity resistant starch-chitosan complex coagulant product prepared using the method described in this application is better coated by the chitosan coating layer. This better coating of corn starch effectively prevents digestive enzymes (α-amylase and saccharifying enzymes) from contacting the corn starch granules during digestion testing, thereby effectively reducing enzymatic hydrolysis of the corn starch granules and increasing the RS content. Furthermore, the coating of corn starch granules by the chitosan layer hinders their movement within the system, leading to an increase in the viscosity of the high-viscosity resistant starch-chitosan complex coagulant product.

[0059] (5) Scanning electron microscopy test results, such as Figure 6 and Figure 7 As shown, Figure 6 and Figure 7 The magnification is 1000x; from Figure 6 It can be seen that the high-viscosity, digestible starch-chitosan complex coagulated product prepared in Example 1, from a microscopic morphology perspective, mainly exhibits that the chitosan coating layer effectively encapsulates the corn starch and bridges a large number of corn starch particles together, which is consistent with... Figure 5 The fluorescence microscopy images of the high-viscosity, digestible starch-chitosan complex aggregate product prepared in Example 1 shown in the figure correspond to those in the comparative samples prepared in Comparative Examples 4 to 6. From a microscopic morphology perspective, the corn starch particles mostly exist as independent particles, with only a small amount of corn starch bridged together by chitosan. This indicates that in the comparative samples prepared in Comparative Examples 4, 5, and 6, ε-polylysine, type A gelatin, and chitosan oligosaccharides only encapsulate a small amount of corn starch, which is consistent with... Figure 5The fluorescence microscopy test images of the comparative samples prepared in Comparative Examples 4, 5, and 6 shown in the figure correspond to each other.

[0060] from Figure 7 As can be seen from the microscopic morphology, compared with the high-viscosity, digestible starch-chitosan complex prepared in Example 1, the comparative sample prepared in Comparative Example 13 mainly showed that the shape of the corn starch granules was destroyed, and the chitosan also encapsulated the morphologically destroyed corn starch granules, forming several encapsulations of different sizes. Figure 7 Taking the largest encapsulation formed in Comparative Example 13 as an example, the size of this encapsulation is significantly smaller than the size of the encapsulation formed by the chitosan coating layer on corn starch particles in the high viscosity resistant starch-chitosan complex coagulate prepared in Example 1. This indicates that drying the initial product of corn starch-chitosan liquid complex coagulate in Comparative Example 13 not only destroys the morphology of corn starch particles, but also the size of the encapsulation formed by chitosan coating the morphologically destroyed corn starch particles is significantly smaller than the size of the encapsulation formed by the chitosan coating layer on corn starch particles in the high viscosity resistant starch-chitosan complex coagulate prepared in Example 1. In other words, when using the same mass of corn starch granules to prepare the high-viscosity resistant starch-chitosan complex aggregate described in Example 1 and the comparative sample described in Comparative Example 13, the surface area of ​​the high-viscosity resistant starch-chitosan complex aggregate prepared in Example 1 is smaller than that of the comparative sample prepared in Comparative Example 13. Therefore, during digestion testing, the contact area between the corn starch granules and digestive enzymes (α-amylase and saccharifying enzyme) in the comparative sample prepared in Comparative Example 13 is larger than that in the high-viscosity resistant starch-chitosan complex aggregate prepared in Example 1. This results in a stronger enzymatic hydrolysis reaction in the comparative sample prepared in Comparative Example 13 compared to that in the high-viscosity resistant starch-chitosan complex aggregate prepared in Example 1. Consequently, the RS content of the comparative sample prepared in Comparative Example 13 is lower than that in the high-viscosity resistant starch-chitosan complex aggregate prepared in Example 1. Furthermore, the morphology of the corn starch granules in the comparative sample prepared in Comparative Example 13 is disrupted. Figure 7 In the study, it can be seen that there are pores on the damaged corn starch granules. The presence of these pores will make it easier for digestive enzymes to enter the damaged corn starch granules and further carry out enzymatic hydrolysis, resulting in a further reduction of RS content in corn starch. Therefore, the antidigestion performance of the comparative sample prepared in Comparative Example 13 is weaker than that of the high viscosity antidigestion starch-chitosan complex coagulant prepared in Example 1 of this application.

[0061] In addition, from Figure 7It can also be seen that, in Comparative Example 14, the comparative sample prepared by directly freeze-drying the initial corn starch-chitosan liquid complex coagulate, shows that the chitosan coating layer can effectively encapsulate the corn starch. However, compared with the effect of the chitosan coating layer on corn starch encapsulation in the high-viscosity, digestible starch-chitosan complex coagulate prepared in Example 1, the chitosan coating layer in the comparative sample prepared in Comparative Example 14 has the following defects: the corn starch particles in the encapsulated material are relatively dispersed and not tightly packed. During digestion testing, the corn starch particles and the digestive system react poorly. The increased contact area of ​​the enzymes (α-amylase and saccharifying enzyme) resulted in a stronger enzymatic hydrolysis reaction in the comparative sample prepared in Comparative Example 14 compared to that in the high-viscosity resistant starch-chitosan complex coagulate prepared in Example 1. Consequently, the RS content of the comparative sample prepared in Comparative Example 14 was lower than that in the high-viscosity resistant starch-chitosan complex coagulate prepared in Example 1. Furthermore, due to the relatively dispersed and loose arrangement of corn starch particles in the encapsulation, the fluidity of the encapsulation increased, leading to a lower final viscosity value for the comparative sample prepared in Comparative Example 14 compared to that of the high-viscosity resistant starch-chitosan complex coagulate prepared in Example 1.

[0062] application: Application Example 1: This application applies high-viscosity resistant starch-chitosan complex coagulated product powder to the preparation of hydrogels. The preparation method is as follows: 0.65 g of the high-viscosity resistant starch-chitosan complex coagulated product prepared in Example 1 is dispersed in 10 ml of water and continuously stirred at 40°C for 30 min to form a suspension; then the suspension is stirred and heated at 95°C for 30 min, and then cooled for 2 h to obtain the complex coagulated hydrogel.

[0063] Control group: Compare with Example 1: 0.5 g of corn starch was dispersed in 10 mL of water and stirred continuously at 40 °C for 30 min to obtain a control solution; then the control solution was stirred and heated at 95 °C for 30 min and then cooled for 2 h to obtain a control hydrogel.

[0064] This application also uses the International Initiative for Standardization of Dietary Disorders for Dysphagia (Spoon Tilting Test) to measure the complex aggregate hydrogel prepared in Example 1 and the control hydrogel prepared in Control Example 1. The test results are as follows: Figure 8 As shown; from Figure 8It can be seen that the complex agglomerate hydrogel prepared in Example 1 has sufficient cohesive force to maintain its shape on a spoon. Furthermore, during spoon tilting, the complex agglomerate hydrogel prepared in Example 1 tilted the entire spoon, and the degree of tilting was greater than that of the control hydrogel prepared in Example 1. This indicates that the complex agglomerate hydrogel prepared in Example 1 is easier to swallow when ingested.

[0065] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-viscosity, resistant-to-digest starch-chitosan complex coagulate, characterized in that: The content of resistant starch (RS) in the high-viscosity resistant starch-chitosan complex coagulate product is 25.75% to 37.56%; the final viscosity of the high-viscosity resistant starch-chitosan complex coagulate product is 2389 cP to 3439 cP.

2. A method for preparing a high-viscosity, digestible starch-chitosan complex aggregate, characterized in that: The high-viscosity resistant starch-chitosan complex coagulate is the high-viscosity resistant starch-chitosan complex coagulate as described in claim 1, and the preparation method of the high-viscosity resistant starch-chitosan complex coagulate includes the following steps: S1. Completely dissolve chitosan powder in acetic acid solution to obtain chitosan acetic acid solution; S2. Under stirring conditions, corn starch is added to the chitosan acetate solution to obtain the initial product of corn starch-chitosan liquid complex aggregate; S3. The initial product of corn starch-chitosan liquid complex coagulate is annealed by stirring at 30℃~60℃ for 6h~48h, then freeze-dried, then ground into powder, and passed through an 80~100 mesh sieve to obtain a high viscosity resistant starch-chitosan complex coagulate product.

3. The method for preparing a high-viscosity, digestible starch-chitosan complex aggregate according to claim 2, characterized in that: In step S1, the acetic acid solution is obtained by uniformly mixing acetic acid and ultrapure water; in the acetic acid solution, the mass concentration of acetic acid is 1%, and the mass ratio of chitosan to acetic acid is 1-5:0.5-2.

4. The method for preparing a high-viscosity, digestible starch-chitosan complex aggregate according to claim 2, characterized in that: The specific steps of step S1 are as follows: dissolve chitosan powder in acetic acid solution, and stir at 30℃~60℃ with continuous stirring until the chitosan is completely dissolved to obtain chitosan acetic acid solution; wherein, during the continuous stirring process, the stirring speed is 160rpm~320rpm.

5. The method for preparing a high-viscosity, digestible starch-chitosan complex aggregate according to claim 2, characterized in that: The specific steps of step S2 are as follows: under stirring conditions, corn starch is added to the chitosan acetate solution, and then, under the conditions of 30℃~60℃, stirring is continued for 0.5h~2h to obtain the initial product of corn starch-chitosan liquid complex aggregate; wherein, the stirring speed is 160rpm~320rpm.

6. The method for preparing a high-viscosity, digestible starch-chitosan complex aggregate according to claim 2, characterized in that: In step S2, the mass ratio of chitosan to corn starch is 1-5:10-20.

7. The method for preparing a high-viscosity, digestible starch-chitosan complex aggregate according to claim 2, characterized in that: In step S3, the freeze-drying temperature is -50℃ to -80℃.

8. Application of high-viscosity resistant starch-chitosan complex coagulates in the food industry, wherein the high-viscosity resistant starch-chitosan complex coagulates are those described in claim 1.

9. A hydrogel prepared using high-viscosity, digestible starch-chitosan complex aggregates, characterized in that: Includes the following steps: A high-viscosity resistant starch-chitosan complex coagulate was mixed with water at a mass-to-volume ratio of (0.5-2) g:(5-20) ml. The mixture was stirred continuously at 30°C-60°C for 10-60 min to form a suspension. The suspension was then heated at 90°C-100°C for 20-60 min and cooled for 1-6 h to obtain a hydrogel. The high-viscosity resistant starch-chitosan complex coagulate is the high-viscosity resistant starch-chitosan complex coagulate as described in claim 1.

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