Bionic rs1 type high resistant starch and preparation method and application thereof

Abstract

The application discloses a kind of bionic RS1 type high resistant starch and its preparation method and application.The preparation method includes: making quinoa protein to carry out enzymatic reaction, and prepare quinoa protein hydrolysate;Starch is modified with octenyl succinic anhydride, and OSA starch nanoparticles are prepared;And, the quinoa protein hydrolysate and OSA starch nanoparticles are reacted to form quinoa protein hydrolysate-OSA starch nanoparticles, then add oxidized tannic acid to carry out crosslinking reaction, and bionic RS1 type high resistant starch with thick interface barrier is prepared.The bionic RS1 type high resistant starch prepared by the application has excellent resistant starch content, and has wide application in the development and application field of anti-digestion starch food.

Description

Technical Field

[0001] This invention belongs to the field of food starch modification technology, and relates to a biomimetic RS1 type high-resistance starch, its preparation method and application, and particularly to a biomimetic RS1 type high-resistance starch with a thick interfacial barrier and its preparation method. Background Technology

[0002] In recent years, diet-related chronic diseases, such as type 2 diabetes, cardiovascular disease, and obesity, have become pressing threats to human health. Starch is one of the essential macronutrients in the human diet and a major source of energy. However, the intake of rapidly digested starch leads to a rapid rise in postprandial blood glucose. Based on in vitro hydrolysis time, starch is classified into rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS). Previous studies have shown that RS intake does not cause a rapid rise in postprandial blood glucose; therefore, the development of RS in starchy staple foods could be a key solution to diet-related chronic disease problems.

[0003] Based on the principle of resistance to digestion, starch gluten (RS) can be classified into five types: physically inaccessible starch (RS1), natural granular starch (RS2), retrograded or recrystallized starch (RS3), chemically modified starch (RS4), and starch-lipid complexes (RS5). Natural RS1, with its cell walls constructed of coarse fibers encapsulating starch, effectively blocks amylase infiltration and reduces amylase hydrolysis, thereby increasing RS content. Based on this, biomimetic RS1-type starch can be prepared to increase RS content. A novel method for preparing biomimetic RS1-type starch involves simply mixing it with proteins, non-starch polysaccharides, etc., to encapsulate the starch and prevent contact between starch and digestive enzymes. However, encapsulated starch prepared by simple mixing often exhibits an uneven and discontinuous coating on the starch granule surface, which limits the improvement of digestive resistance. Therefore, finding better encapsulation methods to increase RS content remains a challenge. Summary of the Invention

[0004] The main objective of this invention is to provide a biomimetic RS1 type high-resistant starch, its preparation method, and its application, so as to overcome the shortcomings of the prior art.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] This invention provides a method for preparing biomimetic RS1-type highly resistant starch, comprising:

[0007] Quinoa protein is subjected to an enzymatic reaction to obtain quinoa protein hydrolysate;

[0008] OSA starch nanoparticles were prepared by modifying wheat starch with octenyl succinic anhydride.

[0009] Furthermore, the quinoa protein hydrolysate is reacted with OSA starch nanoparticles to form quinoa protein hydrolysate-OSA starch nanoparticles, and then oxidized tannic acid is added to carry out a cross-linking reaction to obtain a biomimetic RS1 type high-resistance starch with a thick interfacial barrier.

[0010] The present invention also provides a biomimetic RS1 type high-resistance starch prepared by the aforementioned preparation method.

[0011] This invention also provides the use of the aforementioned biomimetic RS1 type high-resistant starch in the preparation of food for diabetic patients.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention proposes a method for preparing biomimetic RS1-type high-resistant starch by coating OSA starch nanoparticles with protein hydrolysate and cross-linking protein hydrolysate. First, OSA starch nanoparticles (RS4-type resistant starch) are prepared by nanoprecipitation-assisted ultrasound and OSA modification. Then, quinoa protein hydrolysate is used as a starch interfacial film to coat the surface of OSA starch nanoparticles through non-covalent interactions to form biomimetic RS1-type resistant starch. Subsequently, biomimetic RS1-type high-resistant starch with a thick interfacial film is obtained through cross-linking reaction between peptide chains of protein hydrolysate mediated by oxidized tannins. This method combines the beneficial properties of RS1 and RS4, and the starch particles have a thick interfacial barrier, which can significantly increase the RS content. This has important practical significance for protecting human health and preventing diabetes and related metabolic problems. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a graph showing the inhibition rate of α-amylase by different concentrations of quinoa protein hydrolysate (QH) in a typical embodiment of the present invention.

[0015] Figure 2 This is a graph showing the SDS, RDS, and RS contents of starch (WS), OSA starch nanoparticles (OSNPs) in Comparative Example 1, biomimetic RS1 resistant starch (QH-OSNPs) in Comparative Example 2, and biomimetic RS1 high resistant starch (QH / OTA-OSNPs) in Example 2 in this invention. Detailed Implementation

[0016] In view of the deficiencies of the prior art, the inventors of this case, through long-term research and extensive practice, have proposed the technical solution of this invention. The technical solution of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0017] Specifically, as one aspect of the technical solution of this invention, a method for preparing a biomimetic RS1 type high-resistance starch includes:

[0018] Quinoa protein is subjected to an enzymatic reaction to obtain quinoa protein hydrolysate;

[0019] OSA starch nanoparticles were prepared by modifying wheat starch with octenyl succinic anhydride.

[0020] Furthermore, the quinoa protein hydrolysate is reacted with OSA starch nanoparticles to form quinoa protein hydrolysate-OSA starch nanoparticles, and then oxidized tannic acid is added to carry out a cross-linking reaction to obtain a biomimetic RS1 type high-resistance starch with a thick interfacial barrier.

[0021] In some preferred embodiments, the preparation method specifically includes: adjusting the pH of the quinoa protein solution to 8-10.5 with an alkaline solution, adding alkaline protease and carrying out an enzymatic reaction for 60 minutes at a temperature of 45°C and a rotation speed of 200 rpm, then terminating the enzymatic reaction by placing it in a boiling water bath, and then centrifuging and freeze-drying to obtain quinoa protein hydrolysate.

[0022] Furthermore, the inhibition rates of α-amylase by different concentrations of quinoa protein hydrolysate (QH) are shown in the figure below. Figure 1 As shown.

[0023] Furthermore, the quinoa protein solution has a mass-volume concentration of 5-15% (w / v, g / ml).

[0024] Furthermore, the alkaline solution includes, but is not limited to, a sodium hydroxide solution.

[0025] Furthermore, the alkaline protease has an enzyme activity of ≥200000 U / g.

[0026] Furthermore, the mass ratio of alkaline protease to quinoa protein is 100-10000U:1g.

[0027] In some preferred embodiments, the preparation method specifically includes:

[0028] Wheat starch suspension was stirred at 80℃ for 30-60 min, then cooled and ultrasonicated. Anhydrous ethanol was added and the precipitate was freeze-dried to obtain starch nanoparticles.

[0029] Furthermore, the starch nanoparticles are mixed with water to form a starch nanoparticle suspension, then octenyl succinic anhydride is added and the pH of the starch nanoparticle suspension is adjusted to 7.4-7.6 using an alkaline solution for reaction. After the reaction is completed, the pH is adjusted to 6.5 and centrifuged and dried to obtain OSA starch nanoparticles.

[0030] Furthermore, the wheat starch suspension has a mass-volume concentration of 1-3% (w / v).

[0031] Furthermore, the concentration of the starch nanoparticle suspension is 1-3% (w / v).

[0032] Furthermore, the mass ratio of the octenyl succinic anhydride to wheat starch is 1 to 3:100.

[0033] Furthermore, the ultrasonic treatment uses a power of 100-300W and an ultrasonic time of 1-4 hours.

[0034] In some preferred embodiments, the preparation method specifically includes: diluting a tannic acid solution with water and adjusting the pH to 9-11 using an alkaline solution, then bubbling the resulting solution with oxygen at 40°C for 1-2 hours to obtain oxidized tannic acid.

[0035] In some preferred embodiments, the preparation method specifically includes:

[0036] Quinoa protein hydrolysate was added to OSA starch nanoparticle suspension, the pH was adjusted to 7-11 with alkaline solution, and the mixture was stirred at 500 rpm for 1-2 hours to obtain quinoa protein hydrolysate-OSA starch nanoparticle solution.

[0037] Furthermore, the oxidized tannic acid was added to a quinoa protein hydrolysate-OSA starch nanoparticle solution and stirred for 4 hours to obtain a biomimetic RS1 type high-resistance starch with a thick interfacial barrier.

[0038] Furthermore, the mass-volume concentration of the OSA starch nanoparticle suspension is 1-5% (w / v).

[0039] Furthermore, the mass ratio of the quinoa protein hydrolysate to OSA starch nanoparticles is 5N30:100.

[0040] Furthermore, the mass ratio of the oxidized tannins to the quinoa protein hydrolysate is 1:2 to 1:5.

[0041] In some preferred embodiments, the preparation method of the biomimetic RS1 type high-resistance starch includes the following steps:

[0042] (1) Alkaline protease (enzyme activity 200000U / g) was added to quinoa protein solution to carry out an enzymatic reaction to obtain quinoa protein hydrolysate;

[0043] (2) OSA starch nanoparticles were prepared from wheat starch through nanoprecipitation, ultrasonic treatment and OSA modification technology;

[0044] (3) Add the quinoa protein hydrolysate obtained in step (1) to the OSA starch nanoparticle suspension obtained in step (2) to obtain quinoa protein-OSA starch nanoparticle solution, and further add oxidized tannins to carry out cross-linking reaction to obtain biomimetic RS1 type high-resistance starch.

[0045] Further, in step (1), the quinoa protein hydrolysate was prepared by preparing a 15% quinoa protein solution. The pH of the quinoa protein solution was adjusted to 10.5 by adding 1M NaOH solution dropwise. Then, alkaline protease (enzyme activity ≥200,000 U / g) was added, and the reaction was carried out at 45℃ and 200 rpm for 60 min for enzymatic reaction. After the reaction was completed, the above solution was placed in boiling water for 5 min to stop the enzymatic hydrolysis. Then, it was centrifuged at 6000×g for 10 min, and the supernatant was collected and freeze-dried to obtain the quinoa protein hydrolysate.

[0046] Furthermore, in step (1), the enzyme to quinoa protein concentration ratio is 0-10000 U / g.

[0047] Further, in step (2), OSA starch nanoparticles were prepared. A wheat starch suspension (3%) was continuously stirred at 80°C for 30 min. After cooling, the solution was sonicated in an ice bath at 25°C, and then anhydrous ethanol (1:2) was added dropwise with continuous stirring. The precipitate was collected and freeze-dried to obtain wheat starch nanoparticles. OSA was added to the starch nanoparticle suspension (3%), and the pH was maintained at 7.4-7.6 using a diluted NaOH solution. After the reaction, the pH was adjusted to 6.5, and the mixture was centrifuged and dried to obtain OSA starch nanoparticles.

[0048] Furthermore, in step (2), the amount of OSA added (based on starch mass) is 1%-3%.

[0049] Furthermore, in step (2), the ultrasonic (300W) treatment time is 1-4 hours.

[0050] Further, in step (3), oxidized tannic acid is prepared by dissolving tannic acid (2%, w / v) in distilled water, then adjusting the pH to 9 with 1M NaOH, and then bubbling the solution with high-purity oxygen (99.5%) at 40°C for 1 h to convert tannic acid into oxidized tannic acid.

[0051] Further, in step (3), the preparation of the biomimetic RS1 type high-resistant starch involves adding a quinoa protein hydrolysate solution dropwise into an OSA starch nanoparticle solution, adjusting the pH with 1M NaOH, and stirring at 500 rpm for 2 hours to obtain a quinoa protein hydrolysate-OSA starch nanoparticle solution. Subsequently, an oxidized tannic acid solution is added dropwise to the above solution, and the mixture is stirred continuously for 4 hours to obtain the biomimetic RS1 type high-resistant starch.

[0052] Furthermore, in step (3), the concentration of OSA starch nanoparticles in the OSA starch nanoparticle suspension is 5% (w / v).

[0053] Furthermore, in step (3), the solution pH is 7-11.

[0054] Furthermore, in step (3), the amount of quinoa protein hydrolysate added (based on the mass of OSA starch nanoparticles) is 5%-30%.

[0055] Furthermore, in step (3), the mass ratio of oxidized tannins to quinoa protein hydrolysate is 1:2 to 1:5.

[0056] This invention adds quinoa protein hydrolysate to an octenyl succinic anhydride (OSA) nanoparticle dispersion, forming a biomimetic RS1 starch solution with OSA starch nanoparticles coated by quinoa protein hydrolysate through non-covalent interactions. Oxidized tannic acid is then added to the above solution, and a cross-linking reaction between the protein hydrolysate peptide chains mediated by oxidized tannic acid is used to prepare a biomimetic RS1-type highly resistant starch with a thick interfacial barrier. The biomimetic RS1-type highly resistant starch provided by this invention has excellent resistant starch content and has wide applications in the development and application of resistant starch foods.

[0057] Another aspect of the present invention provides a biomimetic RS1 type high-resistance starch prepared by the aforementioned preparation method.

[0058] Furthermore, the biomimetic RS1 type high-resistant starch contains more than 50% resistant starch.

[0059] Another aspect of the present invention provides the use of the aforementioned biomimetic RS1 type high-resistant starch in the preparation of food for diabetic patients.

[0060] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0061] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0062] Example 1

[0063] (1) Preparation of quinoa protein hydrolysate

[0064] A 15% quinoa protein solution was prepared, and the pH was adjusted to 10.5 by adding 1M NaOH solution. Then, 5000 U / g alkaline protease was added, and the reaction was carried out at 45℃ and 200 rpm for 60 min to induce an enzymatic reaction. After the reaction, the solution was placed in boiling water for 5 min to stop the enzymatic hydrolysis. The solution was then centrifuged at 6000×g for 10 min, and the supernatant was collected and freeze-dried to obtain the quinoa protein hydrolysate.

[0065] (2) Preparation of OSA starch nanoparticles

[0066] 3g of starch was suspended in 100ml of 0.1M sodium hydroxide solution for 30min. After cooling, the starch suspension was placed in an ultrasonic cell disruptor and ultrasonically treated (300W) at 25℃ with an ice bath for 1h. Subsequently, the solution was centrifuged at 3000×g for 15min, and the precipitate was collected and dried to obtain starch nanoparticles. 3g of starch nanoparticles were then suspended in 100ml of sodium hydroxide solution for 30min. 1% OSA (based on the mass of starch nanoparticles) was added to the starch nanoparticle suspension, and the pH was maintained at 7.4-7.6 using diluted NaOH solution. After the reaction, the pH was adjusted to 6.5, and the mixture was centrifuged and dried to obtain OSA-containing starch nanoparticles.

[0067] (3) Preparation of oxidized tannic acid

[0068] Tannic acid (2%, w / v) was dissolved in distilled water, and the pH was adjusted to 9 using 1M NaOH. The solution was then bubbled with high-purity oxygen (99.5%) at 40°C for 1 hour to convert the tannic acid into oxidized tannic acid.

[0069] (4) Biomimetic RS1 type high-resistant starch

[0070] 10g of OSA starch nanoparticles were added to 200ml of deionized water to form an OSA starch nanoparticle solution. Then, 2g of quinoa protein hydrolysate solution was added dropwise to the above solution. The pH was adjusted to 7 using 1M NaOH, and the mixture was stirred at 500rpm for 2 hours to obtain a quinoa protein-OSA starch nanoparticle composite solution. Subsequently, a solution containing 1g of oxidized tannins was added dropwise to the above solution, and the mixture was stirred continuously for 4 hours to obtain biomimetic RS1 type highly resistant starch.

[0071] Example 2

[0072] (1) Preparation of quinoa protein hydrolysate

[0073] A 15% quinoa protein solution was prepared, and the pH was adjusted to 10.5 by adding 1M NaOH solution. Then, 2000 U / g alkaline protease was added, and the reaction was carried out at 45℃ and 200 rpm for 60 min to induce an enzymatic reaction. After the reaction, the solution was placed in boiling water for 5 min to stop the enzymatic hydrolysis. The solution was then centrifuged at 6000×g for 10 min, and the supernatant was collected and freeze-dried to obtain the quinoa protein hydrolysate.

[0074] (2) Preparation of OSA starch nanoparticles

[0075] 3g of starch was suspended in 100ml of 0.1M sodium hydroxide solution for 30min. After cooling, the starch suspension was placed in an ultrasonic cell disruptor and ultrasonically treated (300W) at 25°C with an ice bath for 2h. Subsequently, the solution was centrifuged at 3000×g for 15min, and the precipitate was collected and dried to obtain starch nanoparticles. 3g of starch nanoparticles were then suspended in 100ml of sodium hydroxide solution for 30min. 1.5% OSA (based on the mass of starch nanoparticles) was added to the starch nanoparticle suspension, and the pH was maintained at 7.4-7.6 using diluted NaOH solution. After the reaction, the pH was adjusted to 6.5, and the mixture was centrifuged and dried to obtain OSA-containing starch nanoparticles.

[0076] (3) Preparation of oxidized tannic acid

[0077] Tannic acid (2%, w / v) was dissolved in distilled water, and the pH was adjusted to 9 using 1M NaOH. The solution was then bubbled with high-purity oxygen (99.5%) at 40°C for 1 hour to convert the tannic acid into oxidized tannic acid.

[0078] (4) Preparation of biomimetic RS1 type high-resistant starch

[0079] 10g of OSA starch nanoparticles were added to 200ml of deionized water to form an OSA starch nanoparticle solution. Then, 0.5g of quinoa protein hydrolysate solution was added dropwise to the above solution. The pH was adjusted to 8 using 1M NaOH, and the mixture was stirred at 500rpm for 2 hours to obtain a quinoa protein-OSA starch nanoparticle composite solution. Subsequently, a solution containing 0.5g of oxidized tannic acid was added dropwise to the above solution, and the mixture was stirred continuously for 4 hours to obtain biomimetic RS1 type highly resistant starch.

[0080] Example 3

[0081] (1) Preparation of quinoa protein hydrolysate

[0082] A 15% quinoa protein solution was prepared, and the pH was adjusted to 10.5 by adding 1M NaOH solution. Then, 10000 U / g alkaline protease was added, and the reaction was carried out at 45℃ and 200 rpm for 60 min to induce an enzymatic reaction. After the reaction, the solution was placed in boiling water for 5 min to stop the enzymatic hydrolysis. The solution was then centrifuged at 6000×g for 10 min, and the supernatant was collected and freeze-dried to obtain the quinoa protein hydrolysate.

[0083] (2) Preparation of OSA starch nanoparticles

[0084] 3g of starch was suspended in 100ml of 0.1M sodium hydroxide solution for 30min. After cooling, the starch suspension was placed in an ultrasonic cell disruptor and ultrasonically treated (300W) at 25℃ with an ice bath for 3h. Subsequently, the solution was centrifuged at 3000×g for 15min, and the precipitate was collected and dried to obtain starch nanoparticles. 3g of starch nanoparticles were then suspended in 100ml of sodium hydroxide solution for 30min. 2% OSA (based on the mass of starch nanoparticles) was added to the starch nanoparticle suspension, and the pH was maintained at 7.4-7.6 using diluted NaOH solution. After the reaction, the pH was adjusted to 6.5, and the mixture was centrifuged and dried to obtain OSA-containing starch nanoparticles.

[0085] (3) Preparation of oxidized tannic acid

[0086] Tannic acid (2%, w / v) was dissolved in distilled water, and the pH was adjusted to 9 using 1M NaOH. The solution was then bubbled with high-purity oxygen (99.5%) at 40°C for 1 hour to convert the tannic acid into oxidized tannic acid.

[0087] (4) Preparation of biomimetic RS1 type high-resistant starch

[0088] 10g of OSA starch nanoparticles were added to 200ml of deionized water to form an OSA starch nanoparticle solution. Then, 1g of quinoa protein hydrolysate solution was added dropwise to the above solution. The pH was adjusted to 9 using 1M NaOH, and the mixture was stirred at 500rpm for 2 hours to obtain a quinoa protein-OSA starch nanoparticle composite solution. Subsequently, a solution containing 0.25g of oxidized tannic acid was added dropwise to the above solution, and the mixture was stirred continuously for 4 hours to obtain biomimetic RS1 type highly resistant starch.

[0089] Example 4

[0090] (1) Preparation of quinoa protein hydrolysate

[0091] A 15% quinoa protein solution was prepared, and the pH was adjusted to 10.5 by adding 1M NaOH solution. Then, 3000 U / g alkaline protease was added, and the reaction was carried out at 45℃ and 200 rpm for 60 min to induce an enzymatic reaction. After the reaction, the solution was placed in boiling water for 5 min to stop the enzymatic hydrolysis. The solution was then centrifuged at 6000×g for 10 min, and the supernatant was collected and freeze-dried to obtain the quinoa protein hydrolysate.

[0092] (2) Preparation of OSA starch nanoparticles

[0093] 3g of starch was suspended in 100ml of 0.1M sodium hydroxide solution for 30min. After cooling, the starch suspension was placed in an ultrasonic cell disruptor and ultrasonically treated (300W) at 25℃ with an ice bath for 4h. Subsequently, the solution was centrifuged at 3000×g for 15min, and the precipitate was collected and dried to obtain starch nanoparticles. 3g of starch nanoparticles were then suspended in 100ml of sodium hydroxide solution for 30min. 2.5% OSA (based on the mass of starch nanoparticles) was added to the starch nanoparticle suspension, and the pH was maintained at 7.4-7.6 using diluted NaOH solution. After the reaction, the pH was adjusted to 6.5, and the mixture was centrifuged and dried to obtain OSA-containing starch nanoparticles.

[0094] (3) Preparation of oxidized tannic acid

[0095] Tannic acid (2%, w / v) was dissolved in distilled water, and the pH was adjusted to 9 using 1M NaOH. The solution was then bubbled with high-purity oxygen (99.5%) at 40°C for 1 hour to convert the tannic acid into oxidized tannic acid.

[0096] (4) Preparation of biomimetic RS1 type high-resistant starch

[0097] 10g of OSA starch nanoparticles were added to 200ml of deionized water to form an OSA starch nanoparticle solution. Then, 3g of quinoa protein hydrolysate solution was added dropwise to the above solution. The pH was adjusted to 10 using 1M NaOH, and the mixture was stirred at 500rpm for 2 hours to obtain a quinoa protein-OSA starch nanoparticle composite solution. Subsequently, a solution containing 0.6g of oxidized tannic acid was added dropwise to the above solution, and the mixture was stirred continuously for 4 hours to obtain biomimetic RS1 type highly resistant starch.

[0098] Example 5

[0099] (1) Preparation of quinoa protein hydrolysate

[0100] A 15% quinoa protein solution was prepared, and the pH was adjusted to 10.5 by adding 1M NaOH solution. Then, 8000 U / g alkaline protease was added, and the reaction was carried out at 45℃ and 200 rpm for 60 min to induce an enzymatic reaction. After the reaction, the solution was placed in boiling water for 5 min to stop the enzymatic hydrolysis. The solution was then centrifuged at 6000×g for 10 min, and the supernatant was collected and freeze-dried to obtain the quinoa protein hydrolysate.

[0101] (2) Preparation of OSA starch nanoparticles

[0102] 3g of starch was suspended in 100ml of 0.1M sodium hydroxide solution for 30min. After cooling, the starch suspension was placed in an ultrasonic cell disruptor and ultrasonically treated (300W) at 25℃ with an ice bath for 3h. Subsequently, the solution was centrifuged at 3000×g for 15min, the precipitate was collected, and dried to obtain starch nanoparticles. 3g of starch nanoparticles were then suspended in 100ml of sodium hydroxide solution for 30min. 3% OSA (based on the mass of starch nanoparticles) was added to the starch nanoparticle suspension, and the pH was maintained at 7.4-7.6 using diluted NaOH solution. After the reaction, the pH was adjusted to 6.5, and the mixture was centrifuged and dried to obtain OSA-containing starch nanoparticles.

[0103] (3) Preparation of oxidized tannic acid

[0104] Tannic acid (2%, w / v) was dissolved in distilled water, and the pH was adjusted to 9 using 1M NaOH. The solution was then bubbled with high-purity oxygen (99.5%) at 40°C for 1 hour to convert the tannic acid into oxidized tannic acid.

[0105] (4) Preparation of biomimetic RS1 type high-resistant starch

[0106] 10g of OSA starch nanoparticles were added to 200ml of deionized water to form an OSA starch nanoparticle solution. Then, 0.5g of quinoa protein hydrolysate was added to the solution, and the pH was adjusted to 11 using 1M NaOH. The mixture was stirred at 500rpm for 2 hours to obtain a quinoa protein-OSA starch nanoparticle composite solution. Subsequently, a solution containing 0.25g of oxidized tannic acid was added dropwise to the solution, and the mixture was stirred continuously for 4 hours to obtain biomimetic RS1 type highly resistant starch.

[0107] Comparative Example 1

[0108] (1) Preparation of OSA starch nanoparticles

[0109] 3g of starch was suspended in 100ml of 0.1M sodium hydroxide solution for 30min. After cooling, the starch suspension was placed in an ultrasonic cell disruptor and ultrasonically treated (300W) at 25℃ with an ice bath for 2h. Subsequently, the solution was centrifuged at 3000×g for 15min, the precipitate was collected, and dried to obtain starch nanoparticles. 3g of starch nanoparticles were then suspended in 100ml of sodium hydroxide solution for 30min. 1.5% OSA (based on the mass of starch nanoparticles) was added to the starch nanoparticle suspension, and the pH was maintained at 7.4-7.6 using diluted NaOH solution. After the reaction, the pH was adjusted to 6.5, and the mixture was centrifuged and dried to obtain OSA-containing starch nanoparticles.

[0110] Comparative Example 2

[0111] (1) Preparation of quinoa protein hydrolysate

[0112] A 15% quinoa protein solution was prepared, and the pH was adjusted to 10.5 by adding 1M NaOH solution. Then, 2000 U / g alkaline protease was added, and the reaction was carried out at 45℃ and 200 rpm for 60 min to induce an enzymatic reaction. After the reaction, the solution was placed in boiling water for 5 min to stop the enzymatic hydrolysis. The solution was then centrifuged at 6000×g for 10 min, and the supernatant was collected and freeze-dried to obtain the quinoa protein hydrolysate.

[0113] (2) Preparation of OSA starch nanoparticles

[0114] 3g of starch was suspended in 100ml of 0.1M sodium hydroxide solution for 30min. After cooling, the starch suspension was placed in an ultrasonic cell disruptor and ultrasonically treated (300W) at 25℃ with an ice bath for 2h. Subsequently, the solution was centrifuged at 3000×g for 15min, the precipitate was collected, and dried to obtain starch nanoparticles. 3g of starch nanoparticles were then suspended in 100ml of sodium hydroxide solution for 30min. 1.5% OSA (based on the mass of starch nanoparticles) was added to the starch nanoparticle suspension, and the pH was maintained at 7.4-7.6 using diluted NaOH solution. After the reaction, the pH was adjusted to 6.5, and the mixture was centrifuged and dried to obtain OSA-containing starch nanoparticles.

[0115] (3) Preparation of biomimetic RS1 type resistant starch

[0116] 10g of OSA starch nanoparticles were added to 200ml of deionized water to form an OSA starch nanoparticle solution. Then, 0.5g of quinoa protein hydrolysate was added to the above solution. The pH was adjusted to 11 using 1M NaOH and stirred at 500rpm for 4h to obtain biomimetic RS1 type resistant starch.

[0117] In summary, the biomimetic RS1-type high-resistance starch obtained by the above-mentioned technical solution of the present invention utilizes quinoa protein hydrolysate coated with OSA starch nanoparticles and quinoa protein hydrolysate cross-linking at the interface of starch nanoparticles to prepare high-resistance starch. This technology combines the beneficial properties of RS1 and RS4, and can significantly increase the RS content.

[0118] Characterization:

[0119] Figure 2 Table 1 shows the SDS, RDS, and RS content of wheat starch (WS), OSA starch nanoparticles (OSNPs) in Comparative Example 1, biomimetic RS1 resistant starch (QH-OSNPs) in Comparative Example 2, and biomimetic RS1 high resistant starch (QH / OTA-OSNPs) in Example 2. The Raman fwhm values ​​and XRD relative crystallinity of wheat starch (WS), OSA starch nanoparticles (OSNPs) in Comparative Example 1, biomimetic RS1 resistant starch (QH-OSNPs) in Comparative Example 2, and biomimetic RS1 high resistant starch (QH / OTA-OSNPs) in Example 2 are also presented.

[0120] Table 1

[0121]

[0122] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0123] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for preparing biomimetic RS1-type highly resistant starch, characterized in that, include: Quinoa protein is subjected to an enzymatic reaction to obtain quinoa protein hydrolysate; Starch was modified with octenyl succinic anhydride to obtain OSA starch nanoparticles. Furthermore, the quinoa protein hydrolysate is reacted with OSA starch nanoparticles to form quinoa protein hydrolysate-OSA starch nanoparticles, and then oxidized tannic acid is added to carry out a cross-linking reaction to obtain a biomimetic RS1 type high-resistance starch with a thick interfacial barrier.

2. The preparation method according to claim 1, characterized in that, Specifically, it includes: The pH of the quinoa protein solution was adjusted to 8-10.5 using an alkaline solution. Alkaline protease was then added, and the enzymatic reaction was carried out at 45℃ and 200 rpm for 60 min. The enzymatic reaction was then terminated by placing the solution in a boiling water bath. After centrifugation and freeze-drying, quinoa protein hydrolysate was obtained.

3. The preparation method according to claim 2, characterized in that: The quinoa protein solution has a mass-volume concentration of 5-15%; And / or, the alkaline solution includes a sodium hydroxide solution; And / or, the alkaline protease has an enzyme activity ≥200,000 U / g; And / or, the mass ratio of the alkaline protease to quinoa protein is 100-10000U:1g.

4. The preparation method according to claim 1, characterized in that, Specifically, it includes: Wheat starch suspension was stirred at 80℃ for 30-60 min, then cooled and ultrasonicated. Anhydrous ethanol was added and the precipitate was freeze-dried to obtain starch nanoparticles. Furthermore, the starch nanoparticles are mixed with water to form a starch nanoparticle suspension, then octenyl succinic anhydride is added and the pH of the starch nanoparticle suspension is adjusted to 7.4-7.6 using an alkaline solution for reaction. After the reaction is completed, the pH is adjusted to 6.5 and centrifuged and dried to obtain OSA starch nanoparticles.

5. The preparation method according to claim 4, characterized in that: The wheat starch suspension has a mass-volume concentration of 1-3%; And / or, the mass-volume concentration of the starch nanoparticle suspension is 1-3%; And / or, the mass ratio of the octenyl succinic anhydride to wheat starch is 1~3:100; And / or, the ultrasonic treatment uses a power of 100-300W and an ultrasonic time of 1-4h.

6. The preparation method according to claim 1, characterized in that, Specifically, it includes: The tannic acid solution was adjusted to pH 9-11 using an alkaline solution, and then the resulting solution was bubbled with oxygen at 40°C for 1-2 hours to obtain oxidized tannic acid.

7. The preparation method according to claim 1, characterized in that, Specifically, it includes: Quinoa protein hydrolysate was added to OSA starch nanoparticle suspension, the pH was adjusted to 7-11 with alkaline solution, and the mixture was stirred at 500 rpm for 1-2 hours to obtain quinoa protein hydrolysate-OSA starch nanoparticle solution. Furthermore, the oxidized tannic acid was added to a quinoa protein hydrolysate-OSA starch nanoparticle solution and stirred for 4 hours to obtain a biomimetic RS1 type high-resistance starch with a thick interfacial barrier.

8. The preparation method according to claim 7, characterized in that: The mass-volume concentration of the OSA starch nanoparticle suspension is 1-5%; And / or, the mass ratio of the quinoa protein hydrolysate to OSA starch nanoparticles is 5~30:100; And / or, the mass ratio of the oxidized tannins to the quinoa protein hydrolysate is 1:2 to 1:

5.

9. A biomimetic RS1-type high-resistance starch prepared by any one of claims 1-8, characterized in that: The biomimetic RS1 type high-resistant starch contains more than 50% resistant starch.

10. The use of the biomimetic RS1 type high-resistant starch according to claim 9 in the preparation of food for diabetic patients.

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