High-resistance starch-lipid-polyphenol ternary complex and preparation method thereof

Abstract

The invention discloses a high-resistance starch-lipid-polyphenol ternary complex and a preparation method thereof, and relates to the field of modified starch. The preparation method comprises the following steps: homogenizing ethanol and polyphenol to prepare a polyphenol solution, homogenizing the polyphenol solution and a starch-lipid compound to prepare a ternary complex solution, stirring and compounding in water bath equipment at 60-70 DEG C, cooling and recrystallizing, centrifuging, washing with alcohol, and freeze-drying to obtain a starch-lipid-polyphenol compound; the polyphenol is catechin and / or caffeic acid; the lipid is fatty acid. According to the starch-lipid compound, an inclusion compound is formed through the hydrophobic effect, hydrogen bond and other binding effects between lipid and starch, then digestion resistance is achieved, meanwhile, polyphenol is compounded through a hydrothermal method to form a V-type ternary compound, polyphenol prevents amylase from moving in starch molecules and shields some enzyme binding sites of a starch chain, and the digestion resistance of the starch-lipid compound is improved. The activity of alpha-amylase is inhibited, and the compounding rate and the digestion resistance can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of modified starch, and in particular to a highly resistant starch-lipid-polyphenol ternary complex and a preparation method thereof. Background Art

[0002] Starch, as the primary carbohydrate in staple foods, is the primary source of metabolic energy for the human body and plays an irreplaceable role. In traditional grain foods, starch is easily digested and absorbed by the human body. During the digestive process, it is hydrolyzed by digestive enzymes into glucose that can be utilized by the body, providing essential nutrients for energy metabolism and vital activities. However, excessive intake and long-term consumption of foods containing rapidly digestible starches have drawbacks such as rapid digestion, high energy content, and large blood sugar fluctuations. These can lead to rapid increases in the blood sugar index and impaired insulin response, posing a threat to human health. In recent years, low-sugar, low-energy foods have gradually gained popularity among consumers, and food nutrition and health have received increasing attention. Therefore, how to regulate the rate and extent of starch digestion in the human digestive tract, reduce its adverse health effects, and enhance its nutritional functions has become a key scientific issue that the staple food industry urgently needs to address in the context of comprehensive health. This coincides with modern society's demand for nutritionally healthy staple foods.

[0003] In recent years, research on starch-lipid complexes has become a hot topic. These complexes belong to the RS5 resistant starch family, with a predominantly V-shaped crystal structure, a hallmark of starch-lipid complex formation. Research has shown that the primary process by which starch and lipid molecules form complexes is as follows: first, water molecules form hydrogen bonds with glucose residues. These hydrogen bonds force the water molecules within the helical structure outward, forming a helical hydrophobic cavity. The hydrophobic interaction facilitates the entry of lipid molecules into the starch helical cavity, forming a starch-lipid complex.

[0004] The formation of starch-lipid complexes can improve starch's digestibility and slow the rapid rise in blood sugar. However, the effect of lipids on starch's digestibility is limited, with problems such as low complexation rate and insignificant resistance. Therefore, based on the current research status and limitations of starch-lipid complexes, further research is needed to enhance the synergy of starch-lipid complexes to significantly improve starch's digestibility. Summary of the Invention

[0005] The present invention provides a highly resistant starch-lipid-polyphenol ternary complex and a preparation method thereof, so as to solve the problems of low compounding rate and insignificant resistance of the current starch-lipid complex, and significantly improve the digestibility resistance of starch.

[0006] In order to solve the above technical problems, one of the purposes of the present invention is to provide a method for preparing a highly resistant starch-lipid-polyphenol ternary complex, comprising the following steps:

[0007] Homogenizing ethanol and polyphenol to prepare a polyphenol solution, homogenizing the polyphenol solution and a starch-lipid complex to prepare a ternary complex solution, stirring and compounding in a water bath at 60-70° C., cooling and recrystallizing, centrifuging, washing with alcohol, and then freeze-drying the precipitate, crushing and sieving to obtain a starch-lipid-polyphenol complex;

[0008] Wherein, the polyphenols are catechins and / or caffeic acid; and the lipids in the starch-lipid complex are fatty acids.

[0009] The starch-lipid complex of the present application utilizes the hydrophobic interaction, hydrogen bonding and other binding interactions between lipids and starch to form an inclusion complex, avoid direct contact between starch and amylase, delay starch digestion, and thus obtain digestibility. At the same time, polyphenols are hydrothermally compounded with the starch-lipid complex, and polyphenols can form a "V-shaped" complex with starch. This is because polyphenols can enter the helical cavity of the amylose molecule through hydrophobic interaction to form a single helical complex, and the single helical structure is closely related to the formation of V-shaped crystals. Subsequently, low-temperature cooling technology is used in combination to further promote the formation of V-type starch-lipid-polyphenol complexes. Polyphenol compounds are secondary metabolites in plants. The non-covalent interaction between polyphenol compounds and starch molecules will promote the starch molecular chains to be arranged more closely, thereby preventing the movement of amylase within the starch molecule, shielding certain enzyme binding sites of the starch chain, inhibiting the activity of α-amylase, and improving digestibility. In addition, the present application uses catechins and caffeic acid polyphenols, and fatty acids as lipids. The fatty acid molecules have a single long-chain alkane structure, and their hydrophobicity is highly matched with the spiral cavity structure of amylose. This structure can be completely embedded in the spiral cavity through hydrophobic action to form a tight V-shaped crystalline complex with higher crystallinity, which hinders the contact of amylase and has strong thermal stability. Through highly ordered crystalline arrangement, a physical barrier is formed, which can effectively block the hydrolysis of glycosidic bonds by α-amylase. Therefore, the composite index of the present application is higher than that of other polyphenols or lipids and starch, and the composite starch-lipid-polyphenol ternary complex has excellent anti-digestion properties.

[0010] As a preferred embodiment, the method for preparing the starch-lipid complex comprises the following steps:

[0011] Water and starch are mixed and homogenized to prepare a suspension, the lipid is added to obtain a binary complex solution, the solution is stirred and compounded in a water bath at 80-90° C., and the solution is centrifuged and washed with alcohol to obtain a starch-lipid complex.

[0012] The starch and lipids of the present application are compounded under neutral conditions to prepare starch-lipid complexes. This is because hydrophobic interaction is the core driving force for the formation of starch-lipid complexes. When the pH is neutral, fatty acids usually maintain a neutral molecular state, which has a high hydrophobicity, and the internal cavity structure of the amylose molecule is also mainly a hydrophobic environment. Therefore, under neutral conditions, lipid molecules can form starch-lipid complexes with amylose through hydrophobic interactions, thereby improving the composite index. If the pH is alkaline, the carboxyl groups (R-COOH) in the fatty acid molecules will be deprotonated and converted into carboxylate ions (R-COO-), which are negatively charged hydrophilic ions, greatly reducing the hydrophobicity of the lipid molecules themselves; at the same time, there may also be electrostatic repulsion between the negatively charged lipid molecules and the uncharged or slightly negatively charged amylose. The combined effect of the above two factors will significantly weaken the binding driving force between the lipid molecules and the internal cavity structure of amylose, thereby causing a decrease in the starch-lipid composite index.

[0013] As a preferred embodiment, the starch is untreated starch and / or treated starch, and the preparation method of the treated starch comprises the following steps:

[0014] (1) mixing an ethanol aqueous solution and untreated starch to prepare a rice starch milk, stirring and adding an alkali solution to adjust the pH to 10-11, stirring for 20-40 minutes, and then adding an acid solution to adjust the pH to neutral to obtain a treated rice starch milk;

[0015] (2) The treated rice starch milk is subjected to ultrasonic treatment, centrifuged, washed and centrifuged to obtain treated rice starch.

[0016] This application uses ethanol and alkali to treat starch. The -OH in the alkali interacts with the -OH on the glucose residues of starch to give the particles a negative charge. The mutual repulsion between molecules promotes the swelling of starch granules, so that the starch double helix structure is unwound into a single helix structure. The excessive expansion of starch granules is suppressed by ethanol, and the starch is induced to form a V-shaped hydrophobic helical cavity structure. Subsequently, ultrasonic treatment is used to promote the expansion of the starch hydrophobic helical cavity through cavitation effect and mechanical action. The physical modification of the multi-level structure of starch granules and the breakage and reorganization of molecular chains make the expansion of the hydrophobic cavity structure inside the starch easier to expose, providing more binding sites for lipid molecules, which is conducive to promoting the full complexation of starch with lipids and polyphenols, further improving the complexation rate and digestibility. Compared with other treatment methods such as high-pressure homogenization, it has a higher complexation index. This is because the sound waves of ultrasonic treatment can be periodically compressed and expanded in the liquid, and the cavitation effect and strong shear force generated cause the starch molecular chains to break and the double helical structure to depolymerize, changing the multi-scale structure of starch.

[0017] As a preferred embodiment, the method for preparing the untreated starch comprises the following steps:

[0018] The starch raw material is crushed, and then soaked in an alkaline solution with a concentration of 0.1-0.5 mol / L at a solid-liquid mass ratio of 1: (2-4), stirred, and adjusted to neutral pH with an acid solution. After centrifugation and water washing, ethanol is added to the precipitate, stirred, centrifuged, water washed, centrifuged, dried, and crushed to obtain untreated starch.

[0019] As a preferred solution, the mass fraction of amylose in the starch raw material is 10wt%-30wt%.

[0020] As a preferred embodiment, the starch raw material is indica rice, which includes 78.23wt% total starch content, 8.3wt% protein, 0.54wt% fat, 10.63wt% moisture and 0.51wt% ash by mass fraction, and the indica rice contains 16.78wt% amylose by mass fraction.

[0021] As a preferred embodiment, the concentration of polyphenols in the polyphenol solution is 0.05-0.5 g / mL.

[0022] As a preferred embodiment, the mass ratio of the polyphenols in the ternary composite solution to the starch added when preparing the starch-lipid composite is (0.5-3):10.

[0023] As a preferred embodiment, the fatty acid is at least one of lauric acid, myristic acid, capric acid, palmitic acid, and stearic acid.

[0024] As a preferred solution, the ternary composite solution is stirred for 30-60 minutes at a stirring rate of 300-600 rpm.

[0025] As a preferred embodiment, the cooling recrystallization temperature is 3-5°C.

[0026] As a preferred embodiment, the freeze-drying temperature is -85°C to -75°C.

[0027] As a preferred solution, the mesh size of the crushed and sieved material is 80 mesh or more.

[0028] As a preferred embodiment, the concentration of starch in the suspension is 0.05-0.5 g / mL.

[0029] As a preferred embodiment, the starch includes at least one of rice starch, corn starch, tapioca starch, glutinous rice starch, and potato starch.

[0030] As a preferred embodiment, the mass ratio of starch to lipid in the binary composite solution is (0.5-3):10.

[0031] As a preferred solution, the binary composite solution is stirred and composited for 20-60 minutes.

[0032] As a preferred embodiment, in step (1) of the method for preparing treated starch, the concentration of ethanol in the ethanol aqueous solution is 50 wt%-80 wt%.

[0033] As a preferred embodiment, in step (1) of the method for preparing treated starch, the concentration of untreated starch in the rice starch milk is 0.05-0.5 g / mL.

[0034] As a preferred embodiment, in step (1) of the method for preparing treated starch, the concentration of the alkali in the alkali solution is 0.1-5 mol / L, and the alkali is at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, and potassium hydroxide.

[0035] As a preferred embodiment, in step (1) of the method for preparing treated starch, the stirring temperature is 30-40°C.

[0036] As a preferred embodiment, in step (1) of the method for preparing treated starch, the concentration of the acid in the acid solution is 0.1-0.5 mol / L, and the acid is at least one of hydrochloric acid, sulfuric acid, phosphoric acid, and acetic acid.

[0037] As a preferred embodiment, in step (2) of the method for preparing treated starch, the ultrasonic power is 250-350 W, and the ultrasonic time is 15-30 min.

[0038] As a preferred embodiment, in the method for preparing untreated starch, the starch raw material has a particle size of 80 mesh or more after being crushed.

[0039] As a preferred embodiment, in the method for preparing untreated starch, the stirring time after adding the alkali solution is 1-3 hours.

[0040] As a preferred embodiment, in the method for preparing untreated starch, the alkali in the alkali solution is at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, and potassium hydroxide; the acid in the acid solution is at least one of hydrochloric acid, sulfuric acid, phosphoric acid, and acetic acid.

[0041] As a preferred embodiment, in the method for preparing untreated starch, ethanol is added to the precipitate at a solid-liquid mass ratio of 1:(1-2).

[0042] As a preferred embodiment, in the method for preparing untreated starch, the stirring time after adding ethanol is 1-3 hours.

[0043] As a preferred embodiment, the centrifugation is carried out at a speed of 3000-6000 r / min for 5-20 min.

[0044] As a preferred embodiment, the alcohol washing and centrifugation is to add ethanol for washing and then centrifuge at a speed of 3000-6000 r / min for 5-20 minutes, and repeat the alcohol washing for more than 2 times.

[0045] As a preferred solution, water washing and centrifugation are as follows: adding water for washing and then centrifuging at a speed of 3000-6000 r / min for 5-20 minutes, and repeating the alcohol washing for more than 2 times.

[0046] In order to solve the above technical problems, the second purpose of the present invention is to provide a highly resistant starch-lipid-polyphenol ternary complex.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. The starch-lipid complex of the present application utilizes the hydrophobic interaction, hydrogen bonding and other binding interactions between lipids and starch to form an inclusion complex, thereby obtaining digestion resistance. At the same time, a hydrothermal method is used to compound polyphenols, which can form a "V-shaped" complex with starch, thereby preventing the movement of amylase within the starch molecule, shielding certain enzyme binding sites of the starch chain, inhibiting the activity of α-amylase, slowing down the digestion rate of starchy foods in the human digestive tract and the release of glucose, maintaining postprandial blood sugar levels, and thus delaying the occurrence of chronic metabolic diseases such as diabetes, obesity, and cardiovascular disease.

[0049] 2. The present application uses ethanol and alkali solution to treat starch, uses the alkali solution to swell the starch granules, and unwinds the double helix structure of the starch into a single helix structure. The excessive expansion of the starch granules is inhibited by ethanol, and the starch is induced to form a V-shaped hydrophobic helical cavity structure. The ultrasonic treatment promotes the expansion of the starch hydrophobic helical cavity through cavitation effect and mechanical action, making the expansion of the hydrophobic cavity structure inside the starch easier to expose, providing more binding sites for lipid molecules, which is conducive to promoting the full complexation of starch with lipids and polyphenols, and further improving the complexation rate and digestibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 : A schematic flow chart of a method for preparing a highly resistant starch-lipid-polyphenol ternary complex in Example 1 of the present invention;

[0051] Figure 2 : Statistical graph of composite index of starch samples finally prepared in Examples 1-3 and Comparative Examples 3-8 of the present invention (Note: RS-Comparative Example 1; GRS-Comparative Example 2; RSLA-Comparative Example 3; EU-RSLA-Comparative Example 4; RSLA-CC-Example 1; RSLA-RA-Comparative Example 6; RSLA-MN-Comparative Example 7; RSLA-CFA-Example 2; EU-RSLA-CFA-Example 3; RSLACFA-Comparative Example 5; RSGML-CFA-Comparative Example 8);

[0052] Figure 3 : The starch samples finally prepared in Examples 1-3 and Comparative Examples 1-8 of the present invention were observed at 4000 cm -1 and 1000cm -1 Infrared spectra of characteristic absorption peaks between (Note: RS-Comparative Example 1; GRS-Comparative Example 2; RSLA-Comparative Example 3; EU-RSLA-Comparative Example 4; RSLA-CC-Example 1; RSLA-RA-Comparative Example 6; RSLA-MN-Comparative Example 7; RSLA-CFA-Example 2; EU-RSLA-CFA-Example 3; RSLACFA-Comparative Example 5; RSGML-CFA-Comparative Example 8);

[0053] Figure 4 : The starch samples finally prepared in Examples 1-3 and Comparative Examples 1-8 of the present invention were observed at 1200 cm -1 and 800cm -1 Infrared spectra of characteristic absorption peaks between (Note: RS-Comparative Example 1; GRS-Comparative Example 2; RSLA-Comparative Example 3; EU-RSLA-Comparative Example 4; RSLA-CC-Example 1; RSLA-RA-Comparative Example 6; RSLA-MN-Comparative Example 7; RSLA-CFA-Example 2; EU-RSLA-CFA-Example 3; RSLACFA-Comparative Example 5; RSGML-CFA-Comparative Example 8);

[0054] Figure 5 : Raman spectra of the starch samples finally prepared in Examples 1-3 and Comparative Examples 1-8 of the present invention (Note: RS-Comparative Example 1; GRS-Comparative Example 2; RSLA-Comparative Example 3; EU-RSLA-Comparative Example 4; RSLA-CC-Example 1; RSLA-RA-Comparative Example 6; RSLA-MN-Comparative Example 7; RSLA-CFA-Example 2; EU-RSLA-CFA-Example 3; RSLACFA-Comparative Example 5; RSGML-CFA-Comparative Example 8);

[0055] Figure 6 : The Raman spectra of the starch samples finally prepared in Examples 1-3 and Comparative Examples 1-8 were measured at 480 cm -1 Statistical chart of the half-maximum width (FWHM) of nearby characteristic peaks (Note: RS-Comparative Example 1; GRS-Comparative Example 2; RSLA-Comparative Example 3; EU-RSLA-Comparative Example 4; RSLA-CC-Example 1; RSLA-RA-Comparative Example 6; RSLA-MN-Comparative Example 7; RSLA-CFA-Example 2; EU-RSLA-CFA-Example 3; RSLACFA-Comparative Example 5; RSGML-CFA-Comparative Example 8);

[0056] Figure 7 :For the starch samples finally prepared in Examples 1-3 and Comparative Examples 1-8 of the present invention 13 C NMR nuclear magnetic resonance spectrum (Note: RS-Comparative Example 1; GRS-Comparative Example 2; RSLA-Comparative Example 3; EU-RSLA-Comparative Example 4; RSLA-CC-Example 1; RSLA-RA-Comparative Example 6; RSLA-MN-Comparative Example 7; RSLA-CFA-Example 2; EU-RSLA-CFA-Example 3; RSLACFA-Comparative Example 5; RSGML-CFA-Comparative Example 8);

[0057] Figure 8 : Statistical charts of single helix and double helix contents of the starch samples finally prepared in Examples 1-3 and Comparative Examples 1-8 of the present invention (Note: RS-Comparative Example 1; GRS-Comparative Example 2; RSLA-Comparative Example 3; EU-RSLA-Comparative Example 4; RSLA-CC-Example 1; RSLA-RA-Comparative Example 6; RSLA-MN-Comparative Example 7; RSLA-CFA-Example 2; EU-RSLA-CFA-Example 3; RSLACFA-Comparative Example 5; RSGML-CFA-Comparative Example 8);

[0058] Figure 9 : X-ray diffraction patterns of the starch samples finally prepared in Examples 1-3 and Comparative Examples 1-8 of the present invention (Note: RS-Comparative Example 1; GRS-Comparative Example 2; RSLA-Comparative Example 3; EU-RSLA-Comparative Example 4; RSLA-CC-Example 1; RSLA-RA-Comparative Example 6; RSLA-MN-Comparative Example 7; RSLA-CFA-Example 2; EU-RSLA-CFA-Example 3; RSLACFA-Comparative Example 5; RSGML-CFA-Comparative Example 8);

[0059] Figure 10 : Statistical charts for determining the V-type crystal content of the starch samples finally prepared in Examples 1-3 of the present invention and Comparative Examples 1-8 (Note: RS-Comparative Example 1; GRS-Comparative Example 2; RSLA-Comparative Example 3; EU-RSLA-Comparative Example 4; RSLA-CC-Example 1; RSLA-RA-Comparative Example 6; RSLA-MN-Comparative Example 7; RSLA-CFA-Example 2; EU-RSLA-CFA-Example 3; RSLACFA-Comparative Example 5; RSGML-CFA-Comparative Example 8);

[0060] Figure 11: Statistical charts for determining the RS, SDS and RDS contents in the starch samples finally prepared in Examples 1-3 and Comparative Examples 1-8 of the present invention (Note: RS - Comparative Example 1; GRS - Comparative Example 2; RSLA - Comparative Example 3; EU-RSLA - Comparative Example 4; RSLA-CC - Example 1; RSLA-RA - Comparative Example 6; RSLA-MN - Comparative Example 7; RSLA-CFA - Example 2; EU-RSLA-CFA - Example 3; RSLACFA - Comparative Example 5; RSGML-CFA - Comparative Example 8). DETAILED DESCRIPTION

[0061] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0062] To further illustrate the present invention, the present invention is described in detail below with reference to the following examples, but they should not be construed as limiting the scope of the present invention. Unless otherwise specified, the sources of the raw materials used in the following examples and comparative examples of the present application are commercially available, and the same raw materials were used in parallel experiments.

[0063] The indica rice used in the following examples and comparative examples is "Tsuen Yu 9028" indica rice containing 78.23 wt% total starch content, 8.3 wt% protein, 0.54 wt% fat, 10.63 wt% moisture, and 0.51 wt% ash, and the indica rice specifically contains 16.78 wt% amylose.

[0064] Example 1

[0065] A method for preparing a highly resistant starch-lipid-polyphenol ternary complex, such as Figure 1 As shown, the following steps are included:

[0066] (1) Grinding indica rice into rice flour with a particle size greater than 80 mesh, soaking the rice flour in a 0.1 mol / L NaOH aqueous solution at a solid-liquid mass ratio of 1:3, stirring for 2 hours, adjusting the pH to 7.0 with a 0.1 mol / L HCl aqueous solution, centrifuging at 4000 r / min for 10 minutes, discarding the supernatant, washing with water and centrifuging three times, adding anhydrous ethanol to the precipitate at a solid-liquid mass ratio of 1:1, stirring for 1 hour, centrifuging at 4000 r / min for 10 minutes, discarding the supernatant, washing with water and centrifuging three times, and drying the precipitate in an oven at 45°C for 12 hours, crushing it and passing it through an 80-mesh sieve to obtain rice starch;

[0067] (2) Distilled water was added to rice starch and homogenized to prepare a suspension with a concentration of 0.1 g / mL. Lipid was added according to a mass ratio of lipid to rice starch of 1:10, and the lipid was lauric acid. The stirring time was 2 min and the stirring rate was 450 rpm. The mixture was then stirred at 85 ° C for 30 min in a water bath. The composite mixture was washed with anhydrous ethanol to remove unreacted lipids, centrifuged at 4000 r / min for 10 min, and the alcohol washing and centrifugation were repeated twice to obtain a starch-lauric acid complex.

[0068] (3) adding anhydrous ethanol to the polyphenol to homogenize and prepare a polyphenol solution with a concentration of 0.1 g / mL, wherein the polyphenol is catechin, and mixing in a constant temperature magnetic stirrer at a temperature of 65°C, a stirring time of 10 min, and a stirring rate of 450 rpm to obtain a polyphenol solution;

[0069] (4) The polyphenol solution was added to the starch-lauric acid complex and homogenized. The stirring time was 2 minutes and the speed was 450 rpm. The mass ratio of polyphenol to rice starch was 1:10. Then, the mixture was stirred at 65 ° C for 45 minutes in a water bath. The composite mixture was placed at 4 ° C for cooling and recrystallization for 2 hours. It was centrifuged at 4000 r / min for 20 minutes. Then, it was washed with anhydrous ethanol to remove the unreacted polyphenols. It was centrifuged at 4000 r / min for 10 minutes. The alcohol washing and centrifugation were repeated twice. Then, the precipitate was quickly frozen at -80 ° C. After it was completely frozen, it was freeze-dried for 24 hours. After drying, it was crushed through an 80-mesh sieve to obtain a starch-lauric acid-catechin complex. The sample was named RSLA-CC.

[0070] Example 2

[0071] A method for preparing a highly resistant starch-lipid-polyphenol ternary complex, wherein each step and the reagents, equipment, and process parameters used in each step are the same as those in Example 1, except that in step (3), the polyphenol is caffeic acid; and in step (4), the prepared sample is a starch-lauric acid-caffeic acid complex, and the sample is named RSLA-CFA.

[0072] Example 3

[0073] A method for preparing a highly resistant starch-lipid-polyphenol ternary complex, such as Figure 1 As shown, the following steps are included:

[0074] (1) Grinding indica rice into rice flour with a particle size greater than 80 mesh, soaking the rice flour in a 0.1 mol / L NaOH aqueous solution at a solid-liquid mass ratio of 1:3, stirring for 2 hours, adjusting the pH to 7.0 with a 0.1 mol / L HCl aqueous solution, centrifuging at 4000 r / min for 10 minutes, discarding the supernatant, washing with water and centrifuging three times, adding anhydrous ethanol to the precipitate at a solid-liquid mass ratio of 1:1, stirring for 1 hour, centrifuging at 4000 r / min for 10 minutes, discarding the supernatant, washing with water and centrifuging three times, and drying the precipitate in an oven at 45°C for 12 hours, crushing it and passing it through an 80-mesh sieve to obtain rice starch;

[0075] (2) adding a 70 wt % ethanol aqueous solution to rice starch and homogenizing to prepare a rice starch milk with a concentration of 0.1 g / mL, placing it in a magnetic constant temperature water bath and stirring at a temperature of 40° C., a speed of 250 rpm, and a time of 30 min. During the stirring process, a 3.0 mol / L NaOH solution was slowly added at a solid-liquid mass ratio of 1:1 to adjust the pH to about 10.6. After the stirring was completed, a 3.0 mol / L HCl solution was added to adjust the pH to neutral to obtain a treated rice starch milk;

[0076] (3) The treated rice starch emulsion was then placed in an ultrasonic crusher at room temperature with an ultrasonic power of 300 W and an ultrasonic time of 20 min. After the ultrasonication, the rice starch emulsion was centrifuged at 6000 rpm for 20 min, the supernatant was discarded, and the emulsion was then washed with distilled water and centrifuged at 4000 rpm for 10 min. The washing and centrifugation were repeated twice to obtain the treated rice starch.

[0077] (4) Distilled water was added to the treated rice starch and homogenized to prepare a suspension with a concentration of 0.1 g / mL. Lipid was added according to a mass ratio of lipid to rice starch of 1:10, and the lipid was lauric acid. The stirring time was 2 min and the stirring rate was 450 rpm. The mixture was then stirred at 85 ° C for 30 min in a water bath. The composite mixture was washed with anhydrous ethanol to remove unreacted lipids, centrifuged at 4000 r / min for 10 min, and the alcohol washing and centrifugation were repeated twice to obtain a starch-lauric acid complex.

[0078] (5) adding anhydrous ethanol to the polyphenol to homogenize and prepare a polyphenol solution with a concentration of 0.1 g / mL, wherein the polyphenol is caffeic acid, and mixing in a constant temperature magnetic stirrer at 65°C, a stirring time of 10 min, and a stirring rate of 450 rpm to obtain a polyphenol solution;

[0079] (6) The polyphenol solution was added to the starch-lauric acid complex and homogenized. The stirring time was 2 minutes and the speed was 450 rpm. The mass ratio of polyphenol to rice starch was 1:10. Then, the mixture was stirred at 65 ° C in a water bath for 45 minutes. The composite mixture was placed at 4 ° C for cooling and recrystallization for 2 hours. It was centrifuged at 4000 r / min for 20 minutes. Then, it was washed with anhydrous ethanol to remove the unreacted polyphenols. It was centrifuged at 4000 r / min for 10 minutes. The alcohol washing and centrifugation were repeated twice. Then, the precipitate was quickly frozen at -80 ° C. After it was completely frozen, it was freeze-dried for 24 hours. After drying, it was crushed through an 80-mesh sieve to obtain a starch-lauric acid-caffeic acid complex. The sample was named EU-RSLA-CFA.

[0080] Comparative Example 1

[0081] A method for preparing rice starch comprises the following steps:

[0082] Indica rice was crushed into rice flour with a particle size greater than 80 mesh. The rice flour was soaked in a 0.1 mol / L NaOH aqueous solution at a solid-liquid mass ratio of 1:3, stirred for 2 hours, and then adjusted to pH 7.0 with a 0.1 mol / L HCl aqueous solution. The mixture was centrifuged at 4000 r / min for 10 minutes, the supernatant was discarded, and the mixture was washed with water and centrifuged three times. The precipitate was then added with anhydrous ethanol at a solid-liquid mass ratio of 1:1, stirred for 1 hour, and centrifuged at 4000 r / min for 10 minutes. The supernatant was discarded, and the mixture was washed with water and centrifuged three times. The precipitate was dried in an oven at 45°C for 12 hours, crushed, and passed through an 80-mesh sieve to obtain rice starch. The sample was named RS.

[0083] Comparative Example 2

[0084] A method for preparing gelatinized rice starch comprises the following steps:

[0085] The indica rice was ground into rice flour with a particle size greater than 80 mesh, and the rice flour was soaked in a 0.1 mol / L NaOH aqueous solution at a solid-liquid mass ratio of 1:3, stirred for 2 hours, and then adjusted to pH 7.0 with a 0.1 mol / L HCl aqueous solution. The mixture was centrifuged at 4000 r / min for 10 minutes, and the supernatant was discarded. The mixture was washed with water and centrifuged three times. Anhydrous ethanol was added to the precipitate at a solid-liquid mass ratio of 1:1, stirred for 1 hour, and then centrifuged at 4000 r / min for 10 minutes. The supernatant was discarded, and the mixture was washed with water and centrifuged three times. The precipitate was dried in an oven at 45° C. for 12 hours, crushed, and passed through an 80-mesh sieve to obtain rice starch.

[0086] (2) Rice starch in distilled water was homogenized to obtain a suspension with a concentration of 0.1 g / mL. The suspension was heated at 85°C for 30 min in a water bath for gelatinization. The gelatinized system was cooled and recrystallized at 4°C for 2 h. The precipitate was then quickly frozen at -80°C. After being completely frozen, it was freeze-dried for 24 h. After drying, it was crushed and passed through an 80-mesh sieve to obtain gelatinized rice starch. The sample was named GRS.

[0087] Comparative Example 3

[0088] A method for preparing a starch-lipid complex, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that step (3) and step (4) are not performed, and the starch-lauric acid complex sample prepared in step (2) is named RSLA.

[0089] Comparative Example 4

[0090] A method for preparing a starch-lipid complex, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 3, except that steps (5) and (6) are not performed, and the starch-lauric acid complex sample prepared in step (4) is named EU-RSLA.

[0091] Comparative Example 5

[0092] A method for preparing a highly resistant starch-lipid-polyphenol ternary complex comprises the following steps:

[0093] (1) Grinding indica rice into rice flour with a particle size greater than 80 mesh, soaking the rice flour in a 0.1 mol / L NaOH aqueous solution at a solid-liquid mass ratio of 1:3, stirring for 2 hours, adjusting the pH to 7.0 with a 0.1 mol / L HCl aqueous solution, centrifuging at 4000 r / min for 10 minutes, discarding the supernatant, washing with water and centrifuging three times, adding anhydrous ethanol to the precipitate at a solid-liquid mass ratio of 1:1, stirring for 1 hour, centrifuging at 4000 r / min for 10 minutes, discarding the supernatant, washing with water and centrifuging three times, and drying the precipitate in an oven at 45°C for 12 hours, crushing it and passing it through an 80-mesh sieve to obtain rice starch;

[0094] (2) Distilled water was added to rice starch and homogenized to prepare a suspension with a concentration of 0.1 g / mL. Lipids and polyphenols were added in a ratio of 1:1:10, with lauric acid as the lipid and caffeic acid as the polyphenol. The stirring time was 2 min and the stirring rate was 450 rpm. The mixture was then stirred at 85°C in a water bath for 30 min. The composite mixture was cooled and recrystallized at 4°C for 2 h, centrifuged at 4000 r / min for 20 min, and then washed with anhydrous ethanol to remove unreacted lipids and polyphenols. The mixture was centrifuged at 4000 r / min for 10 min, and the alcohol washing and centrifugation were repeated twice. The precipitate was then quickly frozen at -80°C. After it was completely frozen, it was freeze-dried for 24 h. After drying, it was crushed through an 80-mesh sieve to obtain a starch-lauric acid-catechin complex. The sample was named RSLACFA.

[0095] Comparative Example 6

[0096] A method for preparing a highly resistant starch-lipid-polyphenol ternary complex, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that in step (3), the polyphenol is resveratrol; and in step (4), the prepared sample is a starch-lauric acid-resveratrol complex, and the sample is named RSLA-RA.

[0097] Comparative Example 7

[0098] A method for preparing a highly resistant starch-lipid-polyphenol ternary complex, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that in step (3), the polyphenol is magnolol; and in step (4), the prepared sample is a starch-lauric acid-magnoliol complex, and the sample is named RSLA-MN.

[0099] Comparative Example 8

[0100] A method for preparing a highly resistant starch-lipid-polyphenol ternary complex, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 2, except that in step (2), the lipid is monolaurin; and in step (4), the prepared sample is a starch-monolaurin-caffeic acid complex, and the sample is named RSGML-CFA.

[0101] Performance testing

[0102] 1. Composite Index: 1.0 g of the sample prepared in Examples 1-3 or Comparative Examples 1 and 3-8 was weighed into a 50 mL centrifuge tube, and distilled water was added to prepare a 10% suspension. The centrifuge tube was then placed in a water bath and heated at 80° C. with stirring for 30 min to completely gelatinize the sample to obtain a gelatinized starch sample, which was then cooled to room temperature. 50 mL of distilled water was added to the gelatinized starch sample, and the mixture was vortexed for 2 min to mix. The mixture was then centrifuged at 4000 r / min for 10 min. 0.5 mL of the supernatant was taken, and 15 mL of distilled water and 2 mL of iodine solution (2.0% KI + 1.3% I2) were added thereto, respectively, and the mixture was uniformly mixed. After standing for 10 min to develop color, the absorbance of the gelatinized starch sample was measured at 690 nm. The measurement was repeated three times for each sample. The gelatinized starch sample of Comparative Example 1 was used as the control group. The Complex Index (CI) was calculated according to the following formula:

[0103]

[0104] Wherein, A0 is the absorbance of gelatinized starch of comparative example 1, A is the absorbance of gelatinized starch samples of Examples 1-3 or comparative examples 3-8, and the composite index CI is as follows: Figure 2 shown.

[0105] 2. Infrared spectroscopy: Fourier transform infrared spectrometer (Nicolet 6700, Thermo Nicolet, USA) was used to analyze the samples of Examples 1-3 and Comparative Examples 1-8 by infrared spectroscopy. The test conditions were as follows: wavelength range 650 cm -1 -4000cm -1 , with a resolution of 4cm -1 , using air as a blank scan background, and performing 64 scans. The collected spectra were analyzed using OMNIC software (OMNIC 8.0) and the 970 cm -1 -1050cm -1 The regional infrared spectrum was transformed by second-order derivative to analyze the internal hydrogen bonding of the starch composite sample. In addition, 1200 cm -1 -800cm -1 The regional infrared spectrum was subjected to Fourier self-deconvolution processing, and the bandwidth was set to 23cm -1 , the enhancement factor was set to 2.3 to obtain the deconvoluted spectrum. -1 and 1022cm -1 The peak intensity of R 1047 / 1022 To characterize the short-range ordered structure of the sample, the infrared spectrum test results are as follows Figure 3-4 shown.

[0106] 3. Raman spectroscopy: Raman spectroscopy was performed on samples of Examples 1-3 and Comparative Examples 1-8 using a laser confocal Raman spectrometer (Invia Reflex, Renishaw, UK). The instrument was calibrated before testing. The silicon wafer was placed at 520 cm -1 Weigh an appropriate amount of sample and spread it evenly on a glass slide. Then place the glass slide in the sample slot and adjust the focus to ensure that the sample image is clear. Then turn off the white light and perform Raman testing under the laser light source. The Raman test conditions are as follows: use a 785nm green diode laser light source with a resolution of 7cm -1 , the scanning range is 3200cm -1 -100cm -1 The Raman spectrum was analyzed and processed using Omnic software to obtain the sample 480cm -1 The full width at half maximum (FWHM) value characterizes the short-range ordered structure of the sample. The Raman spectrum test results are as follows Figure 5-6 shown.

[0107] 4. 13 C NMR nuclear magnetic resonance spectrum: The helical structure of the samples of Examples 1-3 and Comparative Examples 1-8 was analyzed using a solid-state nuclear magnetic resonance spectrometer (AVANCE III HD 400, Bruker, Germany). An appropriate amount of sample was weighed and placed on a 4 mm MAS solid probe for analysis. 13 C NMR test, 13 The C NMR test conditions were as follows: resonance frequency of 150.9 MHz, rotor rotation rate of 10,000 kHz, 90° pulse width of 5 μs, contact time of 1 ms, delay time of 5 s, and accumulation times of at least 2,400 times. All experiments were performed at room temperature (25°C). PeakFit 4.12 software was used to normalize, subtract amorphous structures, and perform peak fitting on the NMR spectra. The amorphous structure, double helix, and single helix contents of the starch composite samples were calculated. The test results are shown in Figure 2. Figure 7-8 shown.

[0108] 5. X-ray diffraction: X-ray diffraction analysis was performed on the samples of Examples 1-3 and Comparative Examples 1-8 using an X-ray diffractometer (MAX2500VL, Rigaku Corporation, Japan). The X-ray diffractometer test conditions were as follows: Cu-Kα radiation with a wavelength of 0.1542 nm, a voltage of 40 kV, a current of 40 mA, a diffraction angle (2θ) scanning range of 5°-50°, a scanning rate of 5° / min, and a step size of 0.05°. The crystallinity of the samples was calculated using MDI Jade 9 software, and the X-ray diffraction spectra were subjected to peak fitting processing using PeakFit 4.12 software to calculate the V-type crystal and A-type crystal content of the samples. The test results are shown in FIG. Figure 9-10shown.

[0109] 6. Digestive performance: Weigh 1.0 g of the sample of Example 1-3 or Comparative Example 1-8 into a 100 mL centrifuge tube and add 5 glass beads (to simulate the gastrointestinal motility environment), add 20 mL of sodium acetate buffer (0.5 mol / L, pH = 5.2), then add 10 mL of mixed enzymatic solution (290 U / mL of porcine pancreatic α-amylase and 15 U / mL of saccharifying enzyme) and vortex for 2 minutes to mix. Then, place the 100 mL centrifuge tube in a constant temperature shaking water bath at 37 ° C and 150 rpm for enzymatic hydrolysis and start timing. At 0 min, 20 min, and 120 min, 1.0 mL of the reaction solution was drawn into a 10 mL centrifuge tube. 5 mL of anhydrous ethanol was added to inactivate the enzyme, and the tube was centrifuged at 4000 r / min for 10 min. Subsequently, 0.25 mL of the supernatant was drawn and the absorbance of the supernatant at 510 nm was measured using a glucose determination kit using a microplate reader (M200PRO, TECAN, Switzerland). The contents of rapidly digestible starch, slowly digestible starch, and resistant starch in the starch-lipid complex sample were calculated according to the following formula:

[0110] RDS(%)=G 20 ×0.9×100%

[0111] SDS (%) = (G 120 -G 20 )×0.9×100%

[0112] RS (%) = 100% - RDS - SDS

[0113] Where G 20 Glucose content in the sample at 20 min of enzymatic hydrolysis, in mmol / L, G 120 The glucose content in the starch sample at 120 min of enzymatic hydrolysis is expressed in mmol / L. RSD is the proportion of rapidly digestible starch; SDS is the proportion of slowly digestible starch; RS is the proportion of resistant starch. The test results of RSD, SDS and RS are shown in the figure below. Figure 11 shown.

[0114] like Figure 2 As shown, the composite index of the starch-lipid complex (RSLA) prepared by conventional hydrothermal treatment in Comparative Example 3 is 49.51%; the composite index of the starch-lipid-polyphenol ternary complex (RSLA-CFA) prepared by conventional hydrothermal treatment in Example 2 is 59.3%, which shows that the addition of polyphenol compounds is beneficial to improving the composite rate between lipid molecules and rice starch. This is because the thermal energy and ethanol solution can promote the rapid dispersion of polyphenol compounds, increase the non-covalent interaction with starch molecules in the system, and promote the composite between polyphenol compounds and starch molecules. Figure 11As shown, the SDS content and RS content in Example 2 are significantly higher than those in Comparative Example 3. This is because the composite polyphenols in Example 2 have α-amylase inhibitory activity, and the non-covalent interaction between the polyphenol compounds and the starch molecules promotes a tighter arrangement of the starch molecular chains, with more short-range ordered and long-range ordered structural regions, making the multi-scale structure of the starch denser, thereby preventing the movement of amylase within the starch molecules, shielding certain enzyme binding sites of the starch chains, reducing the rate and degree of starch hydrolysis, and thus improving the anti-digestion performance of the starch.

[0115] In addition, compared to Example 2, the composite index of starch-lipid-polyphenol complex (EU-RSLA-CFA) prepared by ultrasonic treatment with ethanol and alkali solution in Example 3 was significantly improved to 81.77%. This shows that the combined ultrasonic treatment with ethanol and alkali solution can synergistically form more hydrophobic cavity structures in starch molecules, thereby promoting the adsorption and complexation between starch and lipid molecules. This is because alkali solution can promote the swelling of starch granules and promote the unwinding of the double helix structure of starch into a single helix structure. Ethanol can inhibit the excessive expansion of starch granules and induce starch to form a V-shaped hydrophobic helical cavity structure, which is conducive to the complexation of lipids, polyphenols and starch granules. At the same time, ultrasonic treatment promotes the further expansion of starch hydrophobic helical cavity through cavitation effect and mechanical action, making the hydrophobic cavity structure inside starch more easily exposed, providing more binding sites for lipid and polyphenol molecules, and allowing starch to fully complex with lipids and polyphenols. Figure 11 As shown, the SDS content and RS content in Example 3 are significantly higher than those in Example 2, which indicates that the starch molecules in Example 3 can form more hydrophobic cavity structures, prompting lipid molecules to enter the hydrophobic cavity structures of starch molecules to form single helical complexes, thereby improving the digestion resistance of starch.

[0116] In Comparative Example 5, the starch-lipid-polyphenol complex (RSLACFA) was prepared by hydrothermal addition of starch, lipids, and polyphenols. Compared to Example 2, the composite index of Comparative Example 5 was significantly lower, reaching 53.71%, indicating a reduced composite efficiency. Furthermore, the SDS and RS contents in Comparative Example 5 were significantly reduced, reaching 32.77% and 22.38%, respectively, indicating a reduced digestion resistance. This is because, in Example 2, high-temperature gelatinization unfolded the helical cavity structure of amylose, and lipids preferentially embedded in the helical cavity through hydrophobic interactions, forming a stable V-shaped crystal structure. With the starch-lipid complex serving as a stable skeleton, polyphenols were adsorbed on the surface of the complex or filled in the gaps through hydrogen bonds or hydrophobic interactions. By pre-fixing the lipids, direct competition between polyphenols and lipids was reduced, improving the composite efficiency of polyphenols with the starch-lipid complex, and forming a hierarchical structure of "starch-lipid skeleton + surface polyphenols" with strong digestion resistance. However, during the complexation process between Comparative Example 5 and the helical cavity structure in amylose, polyphenols can interact with lipids through non-covalent binding, and the helical cavity structure of starch (especially amylose) is the key site for its binding with lipids and polyphenols, which may cause polyphenols (hydrophilic) and lipids (hydrophobic) to simultaneously occupy the starch helical cavity and compete for binding sites, resulting in low utilization of the helical cavity; the above two factors will lead to insufficient formation of the complex prepared in Comparative Example 5, low complexation efficiency, and ultimately poor digestion resistance.

[0117] Compared with Example 2, the lipid in the complex of Comparative Example 8 is glyceryl monolaurate. Figure 2 The composite index of Comparative Example 8 is significantly lower than that of Example 2. This is because the composite of Example 2 uses fatty acids as lipids. The fatty acid molecules have a single long-chain alkane structure, and their hydrophobicity is highly compatible with the helical cavity structure of amylose. This structure can completely embed into the helical cavity through hydrophobic interaction to form a tight V-shaped crystalline composite, hindering access by amylase. However, the monolaurin molecule of Comparative Example 8 contains a hydrophilic glycerol group, which is larger and has significant steric hindrance. The composite process must overcome the steric hindrance effect, making it difficult to deeply embed into the helical cavity structure of starch, resulting in poor composite effect between starch and monoglyceride.

[0118] at the same time, Figure 11 The SDS and RS contents of Comparative Example 8 were significantly lower than those of Example 2. This is because the complex formed between starch and fatty acids in Example 2 has higher crystallinity and stronger thermal stability. Its highly ordered crystal arrangement forms a physical barrier, effectively blocking the hydrolysis of glycosidic bonds by α-amylase. However, the monolaurin in Comparative Example 8, due to its larger size and significant steric hindrance, forms a poor complex with starch. The complex has a loose structure, easily dissociates during digestion, and exhibits weak digestion resistance.

[0119] like Figure 3As shown in the infrared spectra, compared with the RS sample of Comparative Example 1, the starch-lipid binary complexes (RSLA, EU-RSLA) of Comparative Examples 3 and 4 have a higher relative humidity at 2850 cm -1 and 1700cm -1 Obvious absorption characteristic peaks appear at the bottom, which are the stretching vibration peak of -CH2 in the lipid molecule and the characteristic absorption peak of -COOH group, respectively. This shows that the lipid molecules enter the helical cavity of the starch molecule through hydrophobic interaction to form a starch-lipid binary complex. Compared with the starch-lipid binary complexes of Comparative Examples 3 and 4 (RSLA, EU-RSLA), the starch-lipid-polyphenol ternary complexes of Examples 2 and 3 (RSLA-CFA, EU-RSLA-CFA) do not have any new absorption peaks or changes in the position of the characteristic peaks. At the same time, Figure 5 As shown in the Raman spectra, compared with the starch-lipid binary complexes of Comparative Examples 3 and 4 (RSLA and EU-RSLA), the starch-lipid-polyphenol ternary complexes of Examples 2 and 3 (RSLA-CFA and EU-RSLA-CFA) showed no new absorption peaks or changes in the positions of characteristic peaks. This indicates that covalent bonds are not formed between the polyphenols and starch molecules, and that the complexation is mainly achieved through non-covalent interactions such as hydrogen bonds.

[0120] Starch sample at 1047cm -1 and 1022cm -1 The changes in the peak intensity of the infrared absorption characteristic peaks near the R 1047 / 1022 (1047cm -1 / 1022cm -1 The ratio of ) can be used to characterize the short-range ordered structure of the starch surface. The absorption characteristic peak wave number corresponding to the sample of this application is 1051cm -1 and 1020cm -1 .like Figure 4 As shown, compared with the starch-lipid binary complexes of Comparative Examples 3 and 4 (RSLA, EU-RSLA), the starch-lipid-polyphenol ternary complexes of Examples 2 and 3 (RSLA-CFA, EU-RSLA-CFA) have short-range ordered structures R 1051 / 1020 Both increased significantly, reaching 1.07 and 1.95 respectively. This is because the polyphenol compounds can form non-covalent interactions such as hydrogen bonds with starch molecules, thereby forming a single helix and a locally dense ordered structure in the system. 1051 / 1020 It is significantly higher than Example 2, which shows that the combined ultrasonic treatment of ethanol and alkali solution can synergistically form more hydrophobic cavity structures in starch molecules, promote the adsorption and complexation between starch and lipid molecules, and thus form a single helix and a locally densely arranged ordered structure in the system.

[0121] 480 cm in Raman spectroscopy-1 The characteristic peak near 480cm is closely related to the short-range ordered structure of starch. Its half-peak width (FWHM) is highly negatively correlated with the degree of short-range order of starch structure. That is, the higher the degree of short-range order of starch structure, the higher the 480cm -1 The smaller the FWHM of the nearby characteristic peaks. Figure 6 As shown, compared with the starch-lipid binary complexes of Comparative Examples 3 and 4 (RSLA, EU-RSLA), the starch-lipid-polyphenol ternary complexes of Examples 2 and 3 (RSLA-CFA, EU-RSLA-CFA) have a 480 cm -1 The FWHM values ​​for both samples were significantly reduced, reaching 11.36 and 8.39, respectively. This indicates that polyphenols can interact with starch molecules through non-covalent interactions such as hydrogen bonds, leading to the formation of single helical and locally densely packed ordered structures within the system. This significantly increases the degree of short-range order in the starch-lipid-polyphenol ternary complex, consistent with the short-range ordered structure results from infrared spectroscopy. Furthermore, the FWHM for Example 3 was significantly higher than that for Example 2, indicating that the combined ultrasonic treatment with ethanol and alkali solution synergistically forms more hydrophobic cavities within the starch molecules, promoting adsorption and recombination between starch and lipid molecules, thereby significantly increasing the degree of short-range order within the system.

[0122] like Figure 7 of 13 As shown in the C NMR nuclear magnetic resonance spectrum, there are four obvious characteristic peaks, namely the C6 characteristic peak (58-64ppm), the overlapping characteristic peaks of C2, C3 and C5 (69-78ppm), the C4 characteristic peak (80-86ppm) and the C1 characteristic peak (97-106ppm). Among them, the C1 characteristic peak is closely related to the single helical structure and double helical structure in starch, and the C4 characteristic peak is closely related to the amorphous structure in starch.

[0123] like Figure 8As shown, compared with the starch-lipid binary complexes of Comparative Examples 3 and 4 (RSLA, EU-RSLA), the starch-lipid-polyphenol ternary complexes of Examples 2 and 3 (RSLA-CFA, EU-RSLA-CFA) showed significantly increased single and double helical contents, with single helical contents of 8.09% and 18.70%, respectively, and double helical contents of 8.26% and 6.52%, respectively. This indicates that polyphenol compounds can, on the one hand, enter the helical cavity of amylose molecules through hydrophobic interaction to form single helical complexes, and on the other hand, because the phenolic hydroxyl or carboxyl groups they contain can form strong intermolecular hydrogen bonds with the hydroxyl groups on the starch molecular chains, promoting the formation of double helical structures of starch molecules. The single helical content of Example 3 was significantly higher than that of Example 2, indicating that the combined ultrasonic treatment of ethanol and alkali solution can synergistically unwind the double helical structure of starch molecules into a single helical structure, induce the starch molecules to form more hydrophobic cavity structures, and promote the entry of lipid molecules into the hydrophobic cavity structures of starch molecules to form single helical complexes.

[0124] like Figure 9 As shown, the rice starch sample (RS) of Comparative Example 1 shows obvious characteristic peaks at 15.4°, 17.4°, 18.2°, and 23.2°, which is a typical A-type crystalline structure. Compared with Comparative Example 1, the gelatinized rice starch sample (GRS) of Comparative Example 2 shows a smaller characteristic peak at 20.3°, indicating that GRS has an A+V type crystalline structure. This may be because starch molecules and endogenous lipids form a starch-lipid binary complex under the action of thermal energy and water molecules. Compared with Comparative Example 2, the starch-lipid binary complexes (RSLA, EU-RSLA) of Comparative Examples 3 and 4 show obvious characteristic peaks at 13.5° and 20.3°, indicating that the starch-lipid binary complex has an A+V type crystalline structure. Compared with the starch-lipid binary complexes of Comparative Examples 3 and 4 (RSLA, EU-RSLA), the starch-lipid-polyphenol ternary complexes of Examples 2 and 3 (RSLA-CFA, EU-RSLA-CFA) did not show any new characteristic peaks and still maintained an A+V type crystalline structure, further demonstrating that the addition of polyphenol compounds did not change the crystalline structure.

[0125] like Figure 10 As shown, compared with the starch-lipid binary complexes of Comparative Examples 3 and 4 (RSLA, EU-RSLA), the V-type crystal content and the A-type crystal content in the starch-lipid-polyphenol ternary complexes of Examples 2 and 6 (RSLA-CFA, EU-RSLA-CFA) were significantly increased, which were 6.58%, 23.81% and 17.43%, 20.14%, respectively, which is consistent with the starch-lipid-polyphenol ternary complex. 13The single helix and double helix content in the C NMR spectrum showed similar trends. This is because polyphenols can, on the one hand, enter the helical cavities of amylose molecules through hydrophobic interactions to form single helical complexes. On the other hand, the phenolic hydroxyl or carboxyl groups they contain can form strong intermolecular hydrogen bonds with the hydroxyl groups on the starch molecular chains, promoting the formation of double helical structures in the starch molecules. Single and double helical structures are closely related to the formation of V-type and A-type crystal structures, resulting in a higher V-type crystal content. Furthermore, the V-type crystal content in Example 3 was significantly higher than that in Example 2, indicating that the combined ultrasonic treatment with ethanol and alkali solution can synergistically induce starch molecules to form more hydrophobic cavities, prompting lipid molecules to enter the hydrophobic cavities of starch molecules to form single helical complexes.

[0126] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for preparing a highly resistant starch-lipid-polyphenol ternary complex, characterized in that: The following steps are involved: Homogenizing ethanol and polyphenol to prepare a polyphenol solution, homogenizing the polyphenol solution and a starch-lipid complex to prepare a ternary complex solution, stirring and compounding in a water bath at 60-70° C., cooling and recrystallizing, centrifuging, washing with alcohol, and then freeze-drying the precipitate, crushing and sieving to obtain a starch-lipid-polyphenol complex; Wherein, the polyphenols are catechins and / or caffeic acid; and the lipids in the starch-lipid complex are fatty acids.

2. The method for preparing the highly resistant starch-lipid-polyphenol ternary complex according to claim 1, wherein: The preparation method of the starch-lipid complex comprises the following steps: Water and starch are mixed and homogenized to prepare a suspension, the lipid is added to obtain a binary complex solution, the solution is stirred and compounded in a water bath at 80-90° C., and the solution is centrifuged and washed with alcohol to obtain a starch-lipid complex.

3. The method for preparing the highly resistant starch-lipid-polyphenol ternary complex according to claim 2, wherein: The starch is untreated starch and / or treated starch, and the preparation method of the treated starch comprises the following steps: (1) mixing an ethanol aqueous solution and untreated starch to prepare a rice starch milk, stirring and adding an alkali solution to adjust the pH to 10-11, stirring for 20-40 minutes, and then adding an acid solution to adjust the pH to neutral to obtain a treated rice starch milk; (2) The treated rice starch milk is subjected to ultrasonic treatment, centrifuged, washed and centrifuged to obtain treated rice starch.

4. The method for preparing the highly resistant starch-lipid-polyphenol ternary complex according to claim 3, wherein: The preparation method of the untreated starch comprises the following steps: The starch raw material is crushed, and then soaked in an alkaline solution with a concentration of 0.1-0.5 mol / L at a solid-liquid mass ratio of 1: (2-4), stirred, and adjusted to neutral pH with an acid solution. After centrifugation and water washing, ethanol is added to the precipitate, stirred, centrifuged, water washed, centrifuged, dried, and crushed to obtain untreated starch.

5. The method for preparing the highly resistant starch-lipid-polyphenol ternary complex according to claim 1, wherein: The concentration of polyphenols in the polyphenol solution is 0.05-0.5 g / mL; and / or, the mass ratio of the polyphenols in the ternary composite solution to the starch added when preparing the starch-lipid composite is (0.5-3):10; and / or, the fatty acid is at least one of lauric acid, myristic acid, capric acid, palmitic acid, and stearic acid; And / or, the ternary composite solution is stirred for 30-60 min at a stirring rate of 300-600 rpm; and / or, the cooling recrystallization temperature is 3-5°C; and / or, the freeze-drying temperature is -85°C to -75°C; And / or, the mesh number of the crushed and sieved sieve is 80 mesh or more.

6. The method for preparing the highly resistant starch-lipid-polyphenol ternary complex according to claim 2, wherein: The concentration of starch in the suspension is 0.05-0.5 g / mL; And / or, the starch comprises at least one of rice starch, corn starch, tapioca starch, glutinous rice starch, and potato starch; and / or, the mass ratio of starch to lipid in the binary composite solution is (0.5-3):10; And / or, the binary composite solution is stirred and composited for 20-60 minutes.

7. The method for preparing the highly resistant starch-lipid-polyphenol ternary complex according to claim 3, wherein: In step (1) of the method for preparing treated starch, the concentration of ethanol in the ethanol aqueous solution is 50 wt%-80 wt%; and / or, in step (1) of the method for preparing treated starch, the concentration of untreated starch in the rice starch milk is 0.05-0.5 g / mL; And / or, in step (1) of the method for preparing treated starch, the concentration of the alkali in the alkali solution is 0.1-5 mol / L, and the alkali is at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, and potassium hydroxide; and / or, in step (1) of the method for preparing treated starch, the stirring temperature is 30-40° C.; And / or, in step (1) of the method for preparing treated starch, the concentration of the acid in the acid solution is 0.1-0.5 mol / L, and the acid is at least one of hydrochloric acid, sulfuric acid, phosphoric acid, and acetic acid; And / or, in step (2) of the method for preparing treated starch, the ultrasonic power is 250-350 W, and the ultrasonic time is 15-30 min.

8. The method for preparing the highly resistant starch-lipid-polyphenol ternary complex according to claim 4, wherein: In the method for preparing untreated starch, the starch raw material has a particle size of 80 mesh or more after being crushed; and / or, in the method for preparing untreated starch, the stirring time after adding the alkali solution is 1-3 hours; And / or, in the method for preparing untreated starch, the alkali in the alkali solution is at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, and potassium hydroxide; the acid in the acid solution is at least one of hydrochloric acid, sulfuric acid, phosphoric acid, and acetic acid; and / or, in the method for preparing untreated starch, ethanol is added to the precipitate at a solid-to-liquid mass ratio of 1:(1-2); And / or, in the method for preparing untreated starch, the stirring time after adding ethanol is 1-3 hours.

9. The method for preparing the highly resistant starch-lipid-polyphenol ternary complex according to any one of claims 1 to 4, characterized in that: Centrifugation is performed at a rate of 3000-6000 r / min for 5-20 min; And / or, alcohol washing and centrifugation are performed by adding ethanol for washing and then centrifuging at a speed of 3000-6000 r / min for 5-20 min, and repeating the alcohol washing for more than 2 times; And / or, the water washing and centrifugation is to add water for washing and then centrifuge at a speed of 3000-6000 r / min for 5-20 minutes, and repeat the alcohol washing for more than 2 times.

10. A highly resistant starch-lipid-polyphenol ternary complex prepared by the method for preparing a highly resistant starch-lipid-polyphenol ternary complex according to any one of claims 1 to 9.

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