Nanoparticles for inhibiting starch digestion and preparation method thereof

Abstract

The stability of polyphenol is improved based on steric hindrance of the nanoparticles, the slow-release characteristic of the polyphenol in the gastrointestinal digestion process is improved, and the problems that traditional starch is easy to digest and hydrolyze, and the like are solved. And the problems of complex preparation steps or unstable polyphenol inhibition digestion caused by resistant starch and slowly digestible starch are solved. And the activity of amylase can be effectively inhibited by continuously releasing polyphenol, so that the digestibility of starch is reduced. And secondly, the polyphenol used in the invention has biological activity, and the prolamin nanoparticles show excellent mucous membrane adhesiveness in gastrointestinal digestion and absorption processes, so that the bioaccessibility of the encapsulated bioactive compound is increased, and the preparation method has higher application value and is suitable for wide popularization and application.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology, and in particular relates to nanoparticles capable of inhibiting starch digestion and a preparation method thereof. Background Art

[0002] Starch, as one of the abundant renewable biopolymers, is the main nutrient and energy reserve in the human diet. It is easy to digest and hydrolyze, which is not conducive to the reduction of post-meal levels. Traditional methods of inhibiting starch digestion include converting starch into resistant starch or slowly digestible starch and adding polyphenols to inhibit the activity of starch digestive enzymes. Although these methods can inhibit starch digestion, there are problems such as complex preparation steps or unstable digestion inhibition activity of polyphenols. Therefore, the development of a nanoparticle that inhibits starch digestion can meet the current needs of people's lives.

[0003] The invention patent application with publication number CN117700776A discloses a method for preparing low GI and high elastic chestnut starch gel, which comprises preparing a chestnut starch aqueous dispersion, heating it to 100-110°C for reaction, cooling and grinding to obtain modified starch; using an ionic aqueous solution containing sodium chloride, citric acid and fructose to disperse the modified starch to obtain a starch emulsion; homogenizing the starch emulsion to obtain a premix; coating and punching holes in the premix, and performing multi-stage frequency conversion heating to obtain a starch gelatinized liquid; mixing ethanol with the starch gelatinized liquid, and keeping it warm at 50-70°C to obtain a starch fluid; extruding the starch fluid into an injection mold, and drying and curing to obtain the prepared chestnut starch gel has a V-shaped structure, a low GI value and high elasticity. However, the starch gelatinization process prepared by this method is cumbersome.

[0004] The invention patent application with publication number CN117844063A discloses a method for preparing high-resistant starch using quercetin, comprising the following steps: extracting total fat from starch using an organic solvent, n-propanol, under high temperature; centrifuging after extraction, washing the obtained starch sample with alcohol, drying, and finally collecting and storing; mixing the total fat-free starch with deionized water, preparing a suspension of a certain concentration, mixing with a certain proportion of quercetin, heating at high temperature and stirring continuously after ultrasonic treatment, and then freeze-drying, grinding, and sieving to obtain resistant starch. However, free quercetin is easily decomposed and loses its starch digestion inhibitory activity.

[0005] The invention patent application with publication number CN114720457A discloses a strategy for inhibiting the digestibility of starch-based foods. Taking wheat starch as an example, green tea, oolong tea and black tea water extracts are added to the completely gelatinized wheat starch at the same ratio (5%). The digestibility of wheat starch after adding different tea water extracts is determined by the active substances in the tea water extract that have the characteristic of reducing starch digestibility, thereby obtaining a strategy for inhibiting the digestibility of starch-based foods. However, this strategy directly mixes the tea water extract with starch, and the stability of polyphenols in the tea water extract is poor.

[0006] Therefore, how to effectively inhibit starch digestion without increasing the production process is an urgent problem that needs to be solved. Summary of the invention

[0007] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0008] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0009] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a nanoparticle that inhibits starch digestion.

[0010] To solve the above technical problems, the present invention provides the following technical solution: a nanoparticle for inhibiting starch digestion, characterized in that the raw material formula of the nanoparticle includes the following raw materials in percentage by mass: 70% to 95% alcohol-soluble protein and 7% to 11% polyphenols.

[0011] As a preferred embodiment of the nanoparticles of the present invention, the alcohol-soluble protein is at least one of wheat alcohol-soluble protein, zein alcohol-soluble protein, hordeum alcohol-soluble protein, kafirin alcohol-soluble protein, highland barley alcohol-soluble protein and their derivatives.

[0012] As a preferred embodiment of the nanoparticles of the present invention, the polyphenol is at least one of resveratrol, curcumin, tea polyphenols, rutin, quercetin, gallic acid, pterostilbene, and cinnamic acid phenol.

[0013] Another object of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing nanoparticles that inhibit starch digestion, characterized in that:

[0014] Dissolve alcohol-soluble protein in ethanol aqueous solution, dissolve polyphenol in alcohol-soluble protein and stir for 2 to 5 hours in the dark to obtain a polyphenol / alcohol-soluble protein mixed solution;

[0015] Under continuous stirring, the mixed solution is added dropwise to deionized water, or deionized water is added to the mixed solution to obtain a polyphenol / alcohol-soluble protein nanoparticle solution, and ethanol in the solution is evaporated to obtain a nanoparticle solution;

[0016] The freshly prepared nanoparticle solution is freeze-dried or spray-dried to obtain polyphenol-loaded nanoparticles.

[0017] As a preferred embodiment of the preparation method of the present invention, the concentration of the ethanol aqueous solution is 60% to 80%.

[0018] As a preferred embodiment of the preparation method of the present invention, wherein: the stirring, wherein the stirring rate is 300-500 rpm.

[0019] As a preferred embodiment of the preparation method of the present invention, the mixed solution is added dropwise into deionized water, wherein the volume ratio of the mixed solution to the deionized water is 1:4 to 1:7.

[0020] As a preferred embodiment of the preparation method of the present invention, the ethanol in the solution is removed by evaporation, wherein the conditions of rotary evaporation are a temperature of 35 to 42° C. and a rotation speed of 30 to 50 rpm.

[0021] As a preferred embodiment of the preparation method of the present invention, the freeze-drying conditions are as follows: the temperature is -50 to 60°C and the freezing time is 48 to 50 hours.

[0022] As a preferred embodiment of the preparation method of the present invention, the spray drying conditions are as follows: the air inlet temperature is 140-180°C and the needle speed is 2-6s.

[0023] Beneficial effects of the present invention:

[0024] Traditional starch products are easy to digest and hydrolyze and are usually considered to be high glycemic index foods, which can cause elevated blood sugar levels after meals. Some inventions add polyphenol compounds directly to starch, which can reduce the digestibility of starch, but affect the gelatinization properties of the starch system, thereby affecting the flavor and quality of starch-based products, and polyphenols have poor stability and are easy to decompose. The present invention provides a nanoparticle loaded with polyphenols, which improves the stability of polyphenols based on the steric hindrance of the nanoparticles, improves its sustained release properties during gastrointestinal digestion, and effectively inhibits the activity of amylase by continuously releasing polyphenols, thereby reducing the digestibility of starch. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0026] Figure 1 These are scanning electron microscope images of the resveratrol-loaded prolamin nanoparticles of Examples 1 to 4.

[0027] Figure 2These are laser confocal microscopy images of wheat starch gel filled with different alcohol-soluble protein nanoparticles in Examples 1 to 4.

[0028] Figure 3 These are laser confocal microscopy images of Example 1 at different stages of simulated gastric and small intestinal digestion.

[0029] Figure 4 To simulate the release rate of resveratrol in nanoparticles at different stages during digestion.

[0030] Figure 5 This is the hydrolysis rate change curve of wheat starch gel in the simulated digestion process.

[0031] Figure 6 Effects of simulated digestion products on α-amylase activity for different samples. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0035] Raw materials used in the present invention: wheat gluten was purchased from Anhui Ante Food Co., Ltd. (Suzhou, China), resveratrol (purity 99%) was purchased from Aladdin Biochemical Technology Co., Ltd. (Shanghai, China), wheat starch, trypsin, pepsin and bile salt were purchased from Yuanye Biotechnology Co., Ltd. (Shanghai, China). α-amylase was purchased from MacLean Biotechnology Co., Ltd. (Shanghai, China).

[0036] Instruments used in the embodiments of the present invention: HC-3514 high-speed centrifuge Anhui Zhongke Zhongjia Scientific Instrument Co., Ltd., XD-52A rotary evaporator Shanghai Xiande Experimental Instrument Co., Ltd., DF-101S collector constant temperature heating magnetic stirrer Changzhou Putian Instrument Manufacturing Co., Ltd., STELLARIS5 laser scanning confocal microscope Leica Corporation, Germany.

[0037] Example 1

[0038] This example is the preparation of nanoparticles that inhibit starch digestion. The nanoparticles that inhibit starch digestion in this example are composed of the following raw materials in the following mass ratio: 9.1% resveratrol and 90.9% wheat prolamin.

[0039] (1) Dissolve 0.6 g of wheat prolamin in 20 g of ethanol aqueous solution; dissolve 0.06 g of resveratrol in the wheat prolamin solution and stir in the dark for 3 hours;

[0040] (2) Under stirring at 400 rpm, the mixed solution obtained in step (1) was added dropwise to deionized water at a ratio of 1:5, and the ethanol in the solution was removed by a rotary evaporator to obtain resveratrol-loaded alcohol-soluble protein nanoparticles.

[0041] The freshly prepared nanoparticle solution is freeze-dried or spray-dried to obtain polyphenol-loaded nanoparticles.

[0042] Example 2

[0043] This example is the preparation of nanoparticles that inhibit starch digestion. The nanoparticles that inhibit starch digestion in this example are composed of the following raw materials in the following mass ratio: 9.1% resveratrol and 90.9% deamidated gliadin.

[0044] (1) dissolving 0.6 g of deamidated gliadin in 20 g of ethanol aqueous solution; dissolving 0.06 g of resveratrol in the deamidated gliadin solution, and stirring in the dark for 3 hours;

[0045] (2) Under stirring at 400 rpm, the mixed solution obtained in step (1) was added dropwise to deionized water at a ratio of 1:5, and the ethanol in the solution was removed by a rotary evaporator to obtain resveratrol-loaded alcohol-soluble protein nanoparticles.

[0046] The freshly prepared nanoparticle solution is freeze-dried or spray-dried to obtain polyphenol-loaded nanoparticles.

[0047] Example 3

[0048] This example is the preparation of nanoparticles that inhibit starch digestion. The nanoparticles that inhibit starch digestion in this example are composed of the following raw materials in the following mass ratio: 9.1% resveratrol and 90.9% zein.

[0049] (1) Dissolve 0.6 g of zein in 20 g of ethanol solution; dissolve 0.06 g of resveratrol in the zein solution and stir for 3 hours in a dark place;

[0050] (2) Under stirring at 400 rpm, the mixed solution obtained in step (1) was added dropwise to deionized water at a ratio of 1:5, and the ethanol in the solution was removed by a rotary evaporator to obtain resveratrol-loaded alcohol-soluble protein nanoparticles.

[0051] The freshly prepared nanoparticle solution is freeze-dried or spray-dried to obtain polyphenol-loaded nanoparticles.

[0052] Example 4

[0053] This example is the preparation of nanoparticles that inhibit starch digestion. The nanoparticles that inhibit starch digestion in this example are composed of the following raw materials in the following mass ratio: 9.1% resveratrol and 90.9% deamidated zein.

[0054] (1) Dissolve 0.6 g of deamidated zein in 20 g of ethanol aqueous solution; dissolve 0.06 g of resveratrol in the deamidated zein solution, and stir in the dark for 3 hours;

[0055] (2) Under stirring at 400 rpm, the mixed solution obtained in step (1) was added dropwise to deionized water at a ratio of 1:5, and the ethanol in the solution was removed by a rotary evaporator to obtain resveratrol-loaded alcohol-soluble protein nanoparticles.

[0056] The freshly prepared nanoparticle solution is freeze-dried or spray-dried to obtain polyphenol-loaded nanoparticles.

[0057] Example 5

[0058] This example is the preparation of nanoparticles that inhibit starch digestion. The nanoparticles that inhibit starch digestion in this example are composed of the following raw materials in the following mass ratio: 9.1% curcumin and 90.9% wheat prolamin.

[0059] (1) Dissolve 0.6 g of wheat prolamin in 20 g of ethanol solution; dissolve 0.06 g of curcumin in the wheat prolamin solution and stir in the dark for 3 hours;

[0060] (2) under stirring at 400 rpm, the mixed solution obtained in step (1) was added dropwise to deionized water at a ratio of 1:5, and ethanol in the solution was removed by a rotary evaporator to obtain curcumin-loaded prolamin nanoparticles.

[0061] The freshly prepared nanoparticle solution is freeze-dried or spray-dried to obtain polyphenol-loaded nanoparticles.

[0062] Example 6

[0063] This embodiment is the preparation of nanoparticle-filled starch gel, comprising the following steps:

[0064] (1) The polyphenol-loaded alcohol-soluble protein nanoparticles prepared in Examples 1 to 5 were respectively mixed with 10% wheat starch, and heated and stirred at 95° C. for 15 min to obtain a gelatinized product;

[0065] (2) The gelatinized product was stored at 4°C for 14 h to obtain nanoparticle-filled starch gel.

[0066] Comparative Example 1

[0067] This comparative example is the preparation of starch gel without adding nanoparticles, comprising the following steps:

[0068] (1) 10% wheat starch and polyphenols were mixed and heated and stirred at 95° C. for 15 min to obtain a gelatinized product;

[0069] The gelatinized product was stored at 4 °C for 14 h to obtain the nanoparticle-filled starch gel.

[0070] Comparative Example 2

[0071] This comparative example is the preparation of starch gel without adding polyphenols, comprising the following steps:

[0072] (1) mixing 10% wheat starch with alcohol-soluble protein nanoparticles, and heating and stirring at 95° C. for 15 min to obtain a gelatinized product;

[0073] (2) The gelatinized product was stored at 4°C for 14 h to obtain nanoparticle-filled starch gel.

[0074] Example 7

[0075] This example is to measure the microstructure of the nanoparticles obtained in Examples 1 to 4, specifically:

[0076] The four alcohol-soluble protein nanoparticles obtained after freeze-drying were evenly applied on double-sided tape, sprayed with gold for 40 seconds, and observed using a scanning electron microscope (SEM) with an accelerating voltage of 3.0 kV. The average particle size and potential measured by diluting the freshly prepared nanoparticle solution 10 times were used as a control. Figure 1 As shown, from left to right are the nanoparticle microstructures of Example 1, Example 2, Example 3, and Example 4.

[0077] The microstructure of the nanoparticles showed that when the mixed solution of prolamin and resveratrol was transferred to an aqueous solution, the concentration of ethanol in the solution decreased, causing the prolamin to form dispersed spherical small particles through a self-assembly process.

[0078] Example 8

[0079] This example is to measure the microstructure of the wheat starch gel digestion process filled with different alcohol-soluble protein nanoparticles prepared in Example 6, specifically:

[0080] The finished gastric digestion products and the digestion products of the small intestine every 1 hour were placed in a boiling water bath for 5 minutes to inactivate the enzymes; the digestion products were stained in the dark for 4 hours using a dye containing 0.2% fluorescein isothiocyanate and rhodamine B; the stained samples were then smeared on a glass slide and observed using a laser confocal microscope.

[0081] The results are as follows Figure 2 As shown, from left to right are the starch gel microstructures of Example 1, Example 2, Example 3, and Example 4. It can be seen that the round particles are all embedded in the pores, and the nanoparticles are successfully filled in the pores of the starch gel.

[0082] Example 9

[0083] This example is a wheat starch gel in vitro simulated digestion test, specifically:

[0084] In vitro digestion consists of three stages, simulating the digestion process in the mouth, stomach, and small intestine. First, a 50 μg / mL flask containing 0.764 mg / mL NaCl, 1.49 mg / mL KCl, and 0.133 mg / mL CaCl was prepared. 2 and 0.863 mg / mL α-amylase (pH 7.0 ± 0.02) in a simulated oral digestive fluid containing 3.10 mg / mL NaCl, 1.10 mg / mL KCl, 1.50 mg / mL CaCl 2 and simulated gastric digestion fluid with 2.65 mg / mL pepsin.

[0085] The prepared wheat starch gel samples filled with different alcohol-soluble protein nanoparticles were mixed with 10 mL of deionized water to adjust the pH to 7.0 ± 0.02, and then 10 mL of simulated oral digestive fluid was added. The resveratrol content of the mixture was the same. All samples were placed in a constant temperature water bath for 5 min (37 ° C, 100 rpm). Next, the suspension digested in the oral stage was mixed with 20 mL of simulated gastric fluid, the mixed solution was adjusted to pH 2.0 ± 0.02, and placed in a constant temperature water bath for 1 h (37 ° C, 100 rpm) to simulate gastric digestion.

[0086] Finally, a simulated small intestinal digestion was performed, and the pH of the sample after gastric digestion was adjusted to 7.0 ± 0.02. A solution containing 8.00 mg / mL bile salt, 7.01 mg / mL NaCl, and 1.11 mg / mL CaCl was added. 2and 1.00 mg / mL pancreatin-containing simulated intestinal fluid (60 mL), and the pH value of the mixed solution was adjusted to 7.0±0.02. The mixture was then placed in a constant temperature water bath for 4 h (37° C., 100 rpm).

[0087] like Figure 3 From left to right are laser confocal microscopy images of Example 1 at the end of simulated stomach and small intestine digestion at different stages of 1h and 3-4h.

[0088] The original digest (10 mL) of each stage was centrifuged at 12000×g for 13 min. The supernatant was collected and the resveratrol content in different samples was determined at 307 nm. The results are shown in Figure 4 shown.

[0089] The results of simulated in vitro digestion of starch gel showed that the resveratrol release rate of wheat alcohol-soluble protein / resveratrol nanoparticles was 18.6% in the simulated oral stage. The controlled release effect of the samples with added starch gel was more significant. The release rate of resveratrol in the nanoparticle-filled starch gel samples was about 10.2%, with no significant difference. Most of the resveratrol in the nanoparticle-filled wheat starch gel samples was released in the simulated small intestine digestion stage. The cumulative release percentage of resveratrol in the nanoparticle-filled starch gel was 82.1% to 93.2%. The release rate of curcumin was close to the degradation rate, maintaining a more stable curcumin concentration in the small intestine, which was more conducive to the digestion and absorption of curcumin in the small intestine and even the colon.

[0090] The results showed that 48.5% to 69.3% of the polyphenols in the starch gel were released in the small intestine stage. This is consistent with the presence of undigested starch gel samples at the end of the gastric digestion stage. Most of the polyphenol-loaded nanoparticles are still filled in the wheat starch gel and released during the small intestine digestion process. Further filling the polyphenol-loaded nanoparticles in the wheat starch gel can effectively reduce the release of polyphenols during gastric digestion and promote the delivery of polyphenols to the small intestine for digestion and absorption.

[0091] Example 10

[0092] This example is to measure the hydrolysis rate change of wheat starch gel filled with wheat prolamin and deamidated prolamin nanoparticles prepared in Example 6 and the wheat starch of Comparative Example 1 and Comparative Example 2, specifically:

[0093] In vitro digestion was performed, and samples were taken at the mouth, the end of stomach digestion, and the small intestine every 1 hour to obtain 2 mL of products from different samples at different digestion stages. 5 mL of anhydrous ethanol was added to inactivate the enzyme. After centrifugation of different samples, the supernatant was taken and the glucose content of each sample solution was determined using a glucose determination kit. The results are shown in Figure 5 shown.

[0094] The hydrolysis results of wheat starch gel in the simulated digestion process showed the effect of adding composite nanoparticles and separate resveratrol and alcohol-soluble proteins on the hydrolysis rate of wheat starch during digestion. As digestion progresses, the starch gel is gradually digested and decomposed under the action of multiple enzymes. At the end of the simulated oral and gastric digestion stage, there was no significant difference in the hydrolysis rate of wheat starch gel without and with different samples, and the starch hydrolysis rate of different samples was about 5%. The above phenomenon may be due to the retrogradation of starch paste during the preparation of starch gel, the increase in the content of digestion-resistant and resistant starch, and the reduction of starch digestibility, resulting in the samples filled in the starch gel being mostly retained after digestion in the oral and gastric stages. In the simulated small intestinal digestion stage, the hydrolysis rates of starch gels with added resveratrol and prolamin were 15.31%, 21.19%, and 20.93%, respectively. The hydrolysis rates of starch gels with added wheat prolamin / resveratrol and deamidated prolamin / resveratrol nanoparticles were all about 18.30%. The hydrolysis rate of starch gel alone increased rapidly, and the hydrolysis rate of starch reached 31.55% at the end of the first hour of small intestinal digestion, which was significantly higher than that of other samples. At the end of the small intestinal digestion, the starch hydrolysis rate of the starch gel alone was 76.61%; the starch hydrolysis rate of the sample with added resveratrol was 57.70%; the starch hydrolysis rates of the samples with added wheat prolamin and deamidated prolamin were 62.77% and 63.43%, respectively; the starch hydrolysis rate of the sample with added composite nanoparticles was the lowest, at 43.55% and 41.05%, respectively. The above results show that the presence of resveratrol, wheat prolamin and deamidated wheat prolamin can reduce the hydrolysis rate of starch, and resveratrol and prolamin have a synergistic inhibitory effect.

[0095] Embodiment 11

[0096] This example is to measure the activity change of α-amylase during the digestion process of wheat starch gel filled with wheat prolamin and deamidated prolamin nanoparticles prepared in Example 6 and wheat starch gel of Comparative Example 1 and Comparative Example 2, specifically:

[0097] The products of different samples at different digestion stages were centrifuged and the supernatant was collected. The amylase activity was measured using an α-amylase activity kit. The results are shown in Figure 6 shown.

[0098] The results of the effects of different samples on α-amylase activity during digestion showed that the digestion products of starch gel samples alone had little effect on α-amylase activity in the simulated oral, stomach, and small intestine stages, and the activity of amylase remained at around 90%. During the simulated digestion, the starch gel samples with added alcohol-soluble protein, resveratrol, and resveratrol / alcohol-soluble protein composite nanoparticles showed a decreasing trend in amylase activity as the digestion time continued to increase. During the digestion process, the starch gel gradually decomposed, and the alcohol-soluble protein and resveratrol inside it were continuously released. As the digestion time increased, the free alcohol-soluble protein and resveratrol content in the digestive fluid gradually increased, resulting in a decreasing trend in the measured amylase activity. At the end of the simulated digestion, the α-amylase activity of the gel sample with resveratrol added was 51.58%; there was no significant difference in the effects of wheat alcohol-soluble protein and deamidated gliadin on amylase activity, and the α-amylase activity was 68.43% and 68.08%, respectively. The gel samples with alcohol-soluble protein nanoparticles loaded with resveratrol showed the most significant inhibition of α-amylase activity. The results showed that the α-amylase activity of the gel samples with wheat alcohol-soluble protein / resveratrol and deamidated alcohol-soluble protein / resveratrol nanoparticles dropped to 33.10%. In summary, the presence of wheat alcohol-soluble protein, deamidated alcohol-soluble protein and resveratrol all inhibited the activity of α-amylase, and alcohol-soluble protein and resveratrol had a synergistic inhibitory effect. In the simulated digestion process, the presence of alcohol-soluble protein and resveratrol inhibited the activity of α-amylase, resulting in limited digestion and hydrolysis of starch gel. Polyphenols are considered to have enzyme inhibitory activity because of their competitive interaction with proteins. Curcumin and resveratrol partially inactivated α-amylase and amyloglucosidase in vitro.

[0099] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A nanoparticle for inhibiting starch digestion, characterized in that: The raw material formula of the nanoparticles comprises the following raw materials in percentage by mass: 70% to 95% of alcohol-soluble protein and 7% to 11% of polyphenols.

2. The nanoparticle according to claim 1, characterized in that: The alcohol-soluble protein is at least one of wheat alcohol-soluble protein, zein alcohol-soluble protein, hordein alcohol-soluble protein, sorghum alcohol-soluble protein, highland barley alcohol-soluble protein and their derivatives.

3. The nanoparticle according to claim 1, characterized in that: The polyphenol is at least one of resveratrol, curcumin, tea polyphenols, rutin, quercetin, gallic acid, pterostilbene, and cinnamic acid phenol.

4. The method for preparing nanoparticles according to any one of claims 1 to 3, characterized in that: include, Dissolve alcohol-soluble protein in ethanol aqueous solution, dissolve polyphenol in alcohol-soluble protein and stir for 2 to 5 hours in the dark to obtain a polyphenol / alcohol-soluble protein mixed solution; Under continuous stirring, the mixed solution is added dropwise to deionized water, or deionized water is added to the mixed solution to obtain a polyphenol / alcohol-soluble protein nanoparticle solution, and ethanol in the solution is evaporated to obtain a nanoparticle solution; The freshly prepared nanoparticle solution is freeze-dried or spray-dried to obtain polyphenol-loaded nanoparticles.

5. The preparation method according to claim 4, characterized in that: The concentration of the ethanol aqueous solution is 60% to 80%.

6. The preparation method according to claim 4, characterized in that: The stirring, wherein the stirring rate is 300-500 rpm.

7. The preparation method according to claim 4, characterized in that: The mixed solution is added dropwise into deionized water, wherein the volume ratio of the mixed solution to the deionized water is 1:4 to 1:

7.

8. The preparation method according to claim 4, characterized in that: The evaporation removes ethanol from the solution, wherein the conditions for rotary evaporation are a temperature of 35 to 42° C. and a rotation speed of 30 to 50 rpm.

9. The preparation method according to claim 4, characterized in that: The freeze-drying conditions are a temperature of -50 to 60°C and a freezing time of 48 to 50 hours.

10. The preparation method according to claim 4, characterized in that: The spray drying conditions are as follows: an inlet air temperature of 140 to 180° C. and a needle speed of 2 to 6 s.

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