Chinese yam starch-polyphenol nano-composite as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of resistant starch, and particularly relates to a Chinese yam starch-polyphenol nano-composite as well as a preparation method and application thereof. According to the preparation method provided by the invention, the gelatinized Chinese yam native starch and the polyphenol compound are compounded in ethanol under the condition of high-speed shearing to form the Chinese yam starch-polyphenol nano-composite with a V-shaped structure, a chemical cross-linking agent is not needed, and the process is simple, convenient, green and environment-friendly. The obtained compound has digestion resistance, has regulation activity on a glycolipid metabolism regulation function, has application potential of improving diet-induced obesity, and can also significantly improve glycolipid metabolism disorder induced by high-fat or high-glucose diet.

Description

Technical Field

[0001] This invention belongs to the field of resistant starch technology, specifically relating to a yam starch-polyphenol nanocomposite, its preparation method, and its application. Background Technology

[0002] Resistant starch (RS) is a type of starch that is difficult to be enzymatically digested and absorbed in the small intestine, but produces a prebiotic effect through microbial fermentation in the large intestine or colon. It has a significant preventive effect against chronic diseases that seriously threaten human health, such as obesity, diabetes, and cardiovascular disease. Adding resistant starch to food does not affect its texture, flavor, or appearance, making it safe and healthy.

[0003] Yam is a plant of the genus Dioscorea (Dioscorea). Dioscorea opposita The dried rhizome of *Dioscorea* (yam) has the effects of tonifying the spleen and stomach, promoting body fluid production and benefiting the lungs, and tonifying the kidneys and astringing essence. Yam contains various active ingredients (such as polysaccharides, saponins, and starch), which have the effects of enhancing immunity, regulating intestinal flora, and treating diabetes, as well as significant anti-inflammatory activity. In addition to containing various small-molecule active ingredients, yam is also rich in starch, with fresh yam containing approximately 16% starch. Although *Dioscorea* plants are generally known for their high resistant starch (RS) content, the RS content in common edible yam varieties is relatively low. Direct consumption is insufficient to meet the needs of functional foods for intestinal health and metabolic regulation, and direct consumption of its starch may even exacerbate obesity. Therefore, increasing the proportion of resistant starch in yam starch through structural modification or nanotechnology has significant development potential.

[0004] In the prior art, self-assembled V-type complexes (RS5) have been reported as a form of resistant starch. However, V-type starch complexes prepared by modification methods such as physical gelatinization or chemical crosslinking still have room for improvement in terms of formation efficiency, structural stability and functional expansion. In addition, they have drawbacks such as high risk of chemical residues, complex processes and low yields. Summary of the Invention

[0005] To address the above-mentioned technical problems, this invention provides a yam starch-polyphenol nanocomposite, its preparation method, and its applications. The preparation method provided by this invention can obtain a yam starch-polyphenol nanocomposite with a V-shaped structure and good structural stability without the need for chemical cross-linking agents. Furthermore, this composite has significant regulatory potential for problems such as abnormal glucose and lipid metabolism induced by high-fat or high-sugar diets.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: The first aspect of this invention provides a method for preparing yam starch-polyphenol nanocomposites, specifically including the following steps: S1. Peel and homogenize the yam, then sieve it. Let the filtrate stand, discard the supernatant, and wash the precipitate repeatedly with distilled water until the supernatant is colorless. Dry the obtained white starch layer, pulverize it, and sieve it to obtain yam raw starch. S2. The yam starch is gelatinized with water, added to anhydrous ethanol, and stirred under high-speed shear conditions of 2000~15000 rpm. Then, a polyphenol compound is added, and stirring is continued under high-speed shear conditions of 2000~15000 rpm. The resulting precipitate is collected, washed with an ethanol aqueous solution, and dried to obtain the yam starch-polyphenol nanocomposite.

[0007] Polyphenols are a class of secondary metabolites widely found in the plant kingdom. They exhibit the potential to improve glucose and lipid metabolism disorders through one or more molecular mechanisms, such as inhibiting digestive enzymes, regulating glucose transport, improving insulin signaling pathways, and regulating key metabolic genes. The phenolic hydroxyl groups in the structure of polyphenol compounds usually give them strong antioxidant capabilities. However, at the same time, they also make them chemically reactive and highly susceptible to oxidative degradation by environmental factors such as pH, temperature, light, and oxygen. This poses a major challenge to their use in food processing, storage, and clinical applications, and also affects their absorption and metabolism in humans or animals, thus impacting their biological activity.

[0008] The method for preparing yam starch-polyphenol nanocomposites provided by this invention completely destroys the original structure of starch, achieving stable composite formation of polyphenol compounds and yam starch through non-covalent interactions, forming a V-shaped composite. This method requires no chemical cross-linking agents and is simple, environmentally friendly. The resulting yam starch-polyphenol nanocomposites not only significantly improve the resistant starch ratio and crystallization stability of yam starch but also enhance the stability of the polyphenol compounds.

[0009] Preferably, the polyphenolic compounds include ferulic acid, curcumin, quercetin, and tea polyphenols.

[0010] Ferulic acid is a polyphenolic compound widely found in grains, vegetables, fruits, and traditional Chinese medicine. Its molecular structure consists of a phenolic core coupled with an elongated side chain, forming a resonance-stable phenoxy group, thus exhibiting excellent antioxidant capacity. Studies have shown that ferulic acid improves glucose metabolism and lipid homeostasis in a high-fat diet-induced obese mouse model. However, ferulic acid is easily oxidized and has poor stability in food systems, making it difficult to form a stable complex with starch. The yam starch-ferulic acid nanocomposite prepared by the method of this invention has a high ferulic acid loading, resistant starch content, and digestive resistance, and exhibits regulatory activity in glucose and lipid metabolism. Animal experiments show that this composite can significantly reduce weight gain and fat deposition under high-fat feeding conditions without changing food intake, demonstrating its potential for improving diet-induced obesity. It also significantly improves glucose and lipid metabolism disorders in high-fat diet-induced mice and has anti-inflammatory activity, helping to maintain the intestinal barrier. Its comprehensive regulation of energy metabolism and lipid homeostasis may be related to its promotion of beneficial bacteria growth and fermentation to produce short-chain fatty acids (SCFAs).

[0011] Curcumin possesses potent anti-inflammatory properties, and its antioxidant effects have been shown to be modulated by concentration under certain conditions, exhibiting a dual action that transitions between antioxidant and pro-oxidative functions in vivo. Furthermore, clinical trials have demonstrated that curcumin has the potential to improve glycemic control in individuals with prediabetes and reduce their risk of developing type II diabetes. It also shows positive effects in improving dyslipidemia and alleviating fatty liver. Quercetin competitively inhibits sodium-glucose cotransporter 1 (SGLT-1), directly reducing the amount of glucose entering cells from the intestinal lumen, potentially indirectly affecting glucose metabolism. Studies have shown that quercetin may also help lower blood pressure, improve endothelial function, and regulate blood lipids. Tea polyphenols are a collective term for polyphenolic substances in tea, primarily composed of six classes of compounds: flavanones, anthocyanins, flavonols, leucines, phenolic acids, and condensed phenolic acids. These compounds have a significant regulatory effect on improving glucose and lipid metabolism. However, the aforementioned polyphenolic compounds have low oral bioavailability, are easily oxidized, and have poor stability, making it difficult for them to directly exert biological activity or form structurally stable complexes with starch. In contrast, the yam starch-curcumin nanocomplex, yam starch-quercetin nanocomplex, and yam starch-tea polyphenol nanocomplex prepared by the method of this invention possess V-shaped structures and exhibit good structural stability and dispersion uniformity. Furthermore, fruit fly experiments have demonstrated that these three nanocomplexes can effectively improve the weight loss induced by a high-sugar diet in fruit flies, significantly reduce excessively high blood glucose and total sugar levels caused by high-sugar culture, and do not simply inhibit sugar metabolism, but may help the body adapt to metabolic stress by preferentially regulating trehalose, an important stress and energy buffer.

[0012] Preferably, the homogenized slurry in S1 is passed through a 100-mesh sieve.

[0013] Preferably, the settling time in S1 is 10-15 hours, and the temperature is 2-6°C.

[0014] More preferably, the settling time in S1 is 12 hours and the temperature is 4°C.

[0015] Preferably, the drying temperature in S1 is 35~45°C.

[0016] More preferably, the drying temperature in S1 is 40°C.

[0017] Preferably, the material in S1 is pulverized and then passed through a 200-mesh sieve.

[0018] Preferably, the gelatinization operation in S2 is as follows: the yam starch is dispersed in distilled water and stirred at 95~98°C for 20~40 minutes.

[0019] More preferably, 1-10g of the yam starch is dispersed in 100-200mL of distilled water.

[0020] Optionally, 5g of raw yam starch is dispersed in 150mL of distilled water and stirred at 95℃ for 30 minutes.

[0021] Preferably, the mass of the polyphenol compound in S2 is 2% to 12% of the mass of the yam starch.

[0022] More preferably, the mass of the polyphenol compound in S2 is 10% of the mass of the yam starch.

[0023] Preferably, before adding the polyphenol compound in S2, the stirring time under the high-speed shear condition is 4 to 6 minutes, and after adding the polyphenol compound, the stirring time under the high-speed shear condition is continued for 8 to 12 minutes.

[0024] More preferably, the high-speed shearing speed in S2 is 10000 rpm, the stirring time under the high-speed shearing condition is 5 minutes before adding the polyphenol compound, and the stirring time under the high-speed shearing condition is 10 minutes after adding the polyphenol compound.

[0025] Preferably, the concentration of the ethanol aqueous solution in S2 is 70%~90% v / v.

[0026] More preferably, the concentration of the ethanol aqueous solution in S2 is 80% v / v.

[0027] Preferably, the drying temperature in S2 is 50~70°C.

[0028] More preferably, the drying temperature in S2 is 60°C.

[0029] The second aspect of the present invention provides a yam starch-polyphenol nanocomposite, which is prepared by the above preparation method.

[0030] A third aspect of the present invention provides the application of the above-mentioned yam starch-polyphenol nanocomposite, including: Its application in the preparation of drugs for the prevention and treatment of obesity; Applications in the preparation of anti-inflammatory drugs; Its application in the preparation of drugs for the prevention and treatment of hyperglycemia; Applications in the preparation of health foods that help control body fat; Applications in the preparation of health food products that help maintain healthy blood lipid (cholesterol / triglyceride) levels; Applications in the preparation of health foods that help maintain healthy blood sugar levels.

[0031] Preferably, the polyphenolic compound is ferulic acid.

[0032] Preferably, the polyphenolic compound is curcumin, quercetin, or tea polyphenol, and the application is: in the preparation of medicines for preventing and treating hyperglycemia, or in the preparation of health foods that help maintain healthy blood sugar levels.

[0033] The fourth aspect of this invention provides a product for improving glucose and lipid metabolism, the active ingredient of which includes the above-mentioned yam starch-polyphenol nanocomposite. The product is a medicine for preventing and treating obesity, or a health food that helps control body fat, helps maintain healthy blood lipid (cholesterol / triglycerides) levels and / or helps maintain healthy blood sugar levels.

[0034] The fifth aspect of the present invention provides an anti-inflammatory drug, the active ingredient of which includes the above-mentioned yam starch-polyphenol nanocomposite, wherein the polyphenol compound is ferulic acid.

[0035] The beneficial effects of this invention are as follows: 1. The preparation method of the yam starch-polyphenol nanocomposite provided by this invention adopts a green and economical nanoprecipitation method. Through high-speed shearing and antisolvent precipitation, polyphenol compounds are compounded and modified with yam starch, increasing the content of resistant starch in yam starch and enhancing its prebiotic effect. This preparation method overcomes the dependence of existing technologies on chemical modification or complex purification, and combines the advantages of clean label safety and simplified process cost, providing an innovative raw material solution for the development of foods for chronic metabolic disease intervention and low-GI products.

[0036] 2. The yam starch-polyphenol nanocomposite prepared by the above method has a V-shaped structure and is structurally stable. Mouse experiments have shown that the yam starch-ferulic acid nanocomposite prepared by the above method has a low glycemic index, high bioavailability, digestive resistance, and glucose and lipid metabolism regulation functions, as well as anti-inflammatory activity. It can be used to prepare drugs for the prevention and treatment of obesity, as well as health foods that help control body fat, maintain healthy blood lipid (cholesterol / triglyceride) levels, and maintain healthy blood sugar levels. It can also be used to prepare anti-inflammatory drugs. Fruit fly experiments have shown that the yam starch-curcumin nanocomposite, yam starch-quercetin nanocomposite, and yam starch-tea polyphenol nanocomposite prepared by the above method can effectively improve the weight loss induced by a high-sugar diet in fruit flies, significantly reduce the excessively high blood glucose and total sugar levels caused by high-sugar culture, and its mechanism of action is not simply to inhibit glucose metabolism, but may help the body adapt to metabolic stress by preferentially regulating trehalose, an important stress and energy buffer. Attached Figure Description

[0037] Figure 1 The FTIR infrared spectrum in Example 1 of this invention; Figure 2 This is the XRD diffraction pattern from Example 1 of the present invention; Figure 3 The particle size distribution in Example 1 of this invention is used for testing; the different letters above the bars in the left figure indicate significant differences between groups. p <0.05); Figure 4 The contents of different digested components and the hydrolysis curves of the samples YRSF, YSFT and YS in Example 1 of this invention are shown. Figure 5 The content of different digested components in samples YSCU, YSQU, and YSPP in Example 1 of this invention is used for testing. Figure 6 This is the composite rate in Example 1 of the present invention; the different letters above the bars in the left figure indicate significant differences between groups ( p <0.05); Figure 7 This invention illustrates the effects of different diets on mouse body weight, liver coefficient, perirenal fat weight, epididymal fat weight, and brown adipose tissue weight in Example 5. Figure A shows the body weight change curve, Figure B shows the final body weight, Figure C shows the average food intake, Figure D shows the liver coefficient, Figure E shows the perirenal white adipose tissue weight, Figure F shows the epididymal white adipose tissue weight, and Figure G shows the brown adipose tissue weight. Different letters above the bars indicate significant differences between groups. p <0.05); Figure 8The graph shows the regulatory effects of different diets on blood glucose in mice in Example 5 of this invention (n=5). Figure A shows the results of the oral glucose tolerance test (OGTT), Figure B shows the results of the insulin tolerance test (ITT), Figure C shows the area under the curve (AUC) of the OGTT, Figure D shows the area under the curve (AUC) of the ITT, Figure E shows fasting blood glucose (FBG), Figure F shows fasting serum insulin (FBI), Figure G shows the insulin sensitivity index (QUICKI), and Figure H shows the insulin resistance index (HOMA-IR). Different letters above the bars indicate significant differences between groups. p <0.05); Figure 9 This is an example of the effects of different diets on blood lipids (n=5) and liver in mice in Example 5 of this invention; Figure A shows triglycerides (TG), Figure B shows total cholesterol (TC), Figure C shows high-density lipoprotein cholesterol (HDL-C), Figure D shows low-density lipoprotein cholesterol (LDL-C), and Figure E shows a comparison of HE (top) stained and Oil Red O stained (bottom) pathological sections; different letters above the bars indicate significant differences between groups. p <0.05); Figure 10 The bar chart shows the serum levels of inflammatory markers in different groups of mice in Example 5 of this invention; the different letters above the bars indicate significant differences between groups. p <0.05); Figure 11 These are representative H&E staining images of mouse colons from different groups in Example 5 of this invention; Figure 12 This is an analysis of the diversity and composition of the gut microbiota in mice of different groups in Example 5 of the present invention; Figures A to D show the bacterial α diversity index; Figures E to F show the principal coordinate analysis (PCoA) based on Bray-Curtis distance, showing the differences in β diversity between groups; Figure G is an NMDS plot showing the differences in community structure; the values ​​in parentheses represent the percentage of variation explained by each axis, the stress value represents the goodness of fit, different colors represent different treatment groups, and the ellipse represents the 95% confidence interval; Figure H is a bar chart of microbial community composition at the phylum level; Figure I is a bar chart of microbial community composition at the genus level; different letters above the bars indicate significant differences between groups (…). p <0.05); Figure 13 The relative abundance of key genera / families selected by LEfSe analysis and LDA scoring in the gut microbiota composition of different groups of mice in Example 5 of this invention; different letters above the bars indicate significant differences between groups. p <0.05); Figure 14 The body morphology of each group of fruit flies in Example 6 of the present invention; Figure 15 The weight of each group of fruit flies in Example 6 of this invention; **** indicates p <0.001; Figure 16 The blood glucose, total sugar, and trehalose levels of each group of fruit flies in Example 6 of this invention; **** indicates p <0.001. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the implementation methods of this invention without inventive effort fall within the protection scope of this invention.

[0039] The resistant starch (RS) content in yam is low, making direct application insufficient to meet the needs of functional foods for gut health and metabolic regulation. Increasing the proportion of resistant starch requires structural modification or nanotechnology. Self-assembled V-type complexes (RS5) are a form of resistant starch, but V-type starch complexes prepared through physical gelatinization or chemical cross-linking require improvement in formation efficiency, structural stability, and functional expansion. They also suffer from drawbacks such as high risk of chemical residues, complex processes, and low yields.

[0040] To address the above problems, this invention provides a method for preparing yam starch-polyphenol nanocomposites, specifically including the following steps: S1. Peel and homogenize the yam, then sieve it. Let the filtrate stand, discard the supernatant, and wash the precipitate repeatedly with distilled water until the supernatant is colorless. Dry the obtained white starch layer, pulverize it, and sieve it to obtain yam raw starch. S2. The yam starch is gelatinized with water, added to ethanol, and stirred under high-speed shear conditions of 2000~15000 rpm. Then, a polyphenol compound is added, and stirring is continued under high-speed shear conditions of 2000~15000 rpm. The resulting precipitate is collected, washed with an ethanol aqueous solution, and dried to obtain the yam starch-polyphenol nanocomposite.

[0041] This invention also provides a yam starch-polyphenol nanocomposite prepared by the above preparation method.

[0042] This invention also provides the application of the above-mentioned yam starch-polyphenol nanocomposite.

[0043] The present invention will be described below through specific embodiments.

[0044] The yam used in the following examples is Chinese yam (Dioscorea opposita Thunb.) produced in Henan Province, China. Ferulic acid was purchased from Tianjin Xiens Opd Technology Co., Ltd., tea polyphenols were purchased from Anaiji Chemical (batch number D9DKRRNE, CAS number: 84650-60-2), and the high-fat feed was XTHF60 (60% fat-based purified feed) from Jiangsu Xietong Pharmaceutical Biotechnology Co., Ltd.

[0045] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, all materials and reagents used in the following examples were obtained commercially.

[0046] Example 1 This embodiment provides a yam starch-ferulic acid nanocomposite (YRSF), the preparation method of which is as follows: 1. Preparation of yam starch Fresh yam was washed, peeled, and cut into chunks. Distilled water was added, and the mixture was blended into a homogenate using a high-speed blender, then passed through a 100-mesh sieve. The resulting filtrate was allowed to stand at 4°C for 12 hours, the supernatant was discarded, and the precipitate was repeatedly washed with distilled water until the supernatant became colorless. The resulting white starch layer was dried at 40°C to constant weight, pulverized, and passed through a 200-mesh sieve to obtain yam native starch (YS), which was then used for preparation. The purity of this starch was 96.3% (dry basis), the protein content was 0.21% ± 0.00%, the lipid content was less than 0.5%, and the amylose content was 32.65% ± 0.6%.

[0047] 2. Combined with ferulic acid Take 5g of raw yam starch, add 150mL of distilled water, and stir at 95℃ for 30 minutes to obtain a gelatinized yam starch slurry; add the gelatinized yam starch slurry dropwise to 600mL of anhydrous ethanol, and stir continuously for 5 minutes under high-speed shear at 10000rpm, then add 0.5g of ferulic acid, and continue stirring under high-speed shear at 10000rpm for 10 minutes, collect the precipitate, wash the precipitate three times with 80% v / v ethanol, and dry at 60℃ to obtain the yam starch-ferulic acid nanocomposite.

[0048] Example 2 This embodiment provides a yam starch-curcumin nanocomposite (YSCU), the preparation method of which is as follows: 1. Preparation of yam starch: Same as in Example 1.

[0049] 2. Combined with curcumin Take 5g of raw yam starch, add 150mL of distilled water, and stir at 95℃ for 30 minutes to obtain a gelatinized yam starch slurry; add the gelatinized yam starch slurry dropwise to 600mL of anhydrous ethanol, and stir continuously for 5 minutes under high-speed shear at 10000rpm, then add 0.5g of curcumin, and continue stirring under high-speed shear at 10000rpm for 10 minutes, collect the precipitate, wash the precipitate three times with 80% v / v ethanol, and dry at 60℃ to obtain the yam starch-curcumin nanocomposite.

[0050] Example 3 This embodiment provides a yam starch-quercetin nanocomposite (YSQU), the preparation method of which is as follows: 1. Preparation of yam starch: Same as in Example 1.

[0051] 2. Combined with quercetin Take 5g of raw yam starch, add 150mL of distilled water, and stir at 95℃ for 30 minutes to obtain a gelatinized yam starch slurry. Add the gelatinized yam starch slurry dropwise to 600mL of anhydrous ethanol, and stir continuously for 5 minutes under high-speed shear at 10000rpm. Then add 0.5g of quercetin, and continue stirring under high-speed shear at 10000rpm for 10 minutes. Collect the precipitate, wash the precipitate three times with 80% v / v ethanol, and dry at 60℃ to obtain the yam starch-quercetin nanocomposite.

[0052] Example 4 This embodiment provides a yam starch-tea polyphenol nanocomposite (YSPP), the preparation method of which is as follows: 1. Preparation of yam starch: Same as in Example 1.

[0053] 2. Combined with tea polyphenols Take 5g of raw yam starch, add 150mL of distilled water, and stir at 95℃ for 30 minutes to obtain a gelatinized yam starch slurry. Add the gelatinized yam starch slurry dropwise to 600mL of anhydrous ethanol, and stir continuously for 5 minutes under high-speed shear at 10000rpm. Then add 0.5g of tea polyphenols, and continue stirring under high-speed shear at 10000rpm for 10 minutes. Collect the precipitate, wash the precipitate three times with 80% v / v ethanol, and dry at 60℃ to obtain the yam starch-tea polyphenol nanocomposite.

[0054] Comparative Example 1 This comparative example provides a physical mixture of yam starch and ferulic acid (YSFT), the preparation method of which is as follows: 1. Preparation of yam starch: Same as in Example 1.

[0055] 2. Compounding with ferulic acid: Take 5g of raw yam starch, add 150mL of distilled water, and stir at 95℃ for 30 minutes to obtain a gelatinized yam starch slurry; add the gelatinized yam starch slurry dropwise to 600mL of anhydrous ethanol, stir at 500rpm for 5 minutes, then add 0.5g of ferulic acid, continue stirring for 10 minutes, collect the precipitate, wash the precipitate three times with 80% ethanol, and dry at 60℃ to obtain a physical mixture of yam starch and ferulic acid.

[0056] Comparative Example 2 This comparative example provides a yam starch + ferulic acid mixture (YSF), the preparation method of which is as follows: 1. Preparation of yam starch: Same as in Example 1.

[0057] 2. Add ferulic acid to yam starch (the mass ratio of yam starch to ferulic acid is 10:1), and stir continuously at room temperature to mix thoroughly to obtain YSF.

[0058] Comparative Example 3 This comparative example provides a type III resistant starch (YRS) derived from yam, and its preparation method is as follows: 1. Preparation of yam starch: Same as in Example 1.

[0059] 2. Disperse 450g of raw yam starch in 1000mL of deionized water to form a starch suspension, and gelatinize it in an autoclave at 121°C (0.115 MPa) for 15 minutes. After cooling the resulting paste to 25°C, let it stand at 4°C for 24 hours to promote starch retrogradation. Dry the retrograded starch at 50°C, grind it, and pass it through a 200-mesh sieve to obtain type III resistant starch YRS from yam.

[0060] Test Example 1 This test example investigated the physicochemical properties and structural characteristics of the yam starch (YS) and yam starch-ferulic acid nanocomposite (YRSF) prepared in Example 1, the yam starch-curcumin nanocomposite (YSCU) prepared in Example 2, the yam starch-quercetin nanocomposite (YSQU) prepared in Example 3, the yam starch-tea polyphenol nanocomposite (YSPP) prepared in Example 4, and the yam starch + ferulic acid physical mixture (YSFT) prepared in Comparative Example 1. These included chemical structural characteristics, crystal structure, particle size distribution, content of different starch components, in vitro enzymatic hydrolysis characteristics, and determination of composite rate.

[0061] (1) Chemical structural characteristics The dried YS, YRSF, YSFT, YSCU, YSQU, and YSPP samples were mixed with potassium bromide at a mass ratio of 1:100–200 and pressed into tablets under vacuum. Data were collected from 4000–4000 cm⁻¹ in transmission mode using a Tensor27 infrared spectrometer (Germany). -1 Infrared spectrum within the range, with a resolution of 4 cm⁻¹ -1 The spectra were scanned 64 times at room temperature. The resulting spectra were smoothed and baseline corrected using OPUS software, then exported as .dpt files, and plotted using Origin 8.5 (OriginLab).

[0062] Infrared spectrum as shown Figure 1 As shown, in the infrared spectra of YRSF, YSCU, YSQU, and YSPP, at 3400 cm⁻¹... -1 A broad absorption band appears at 2927 cm⁻¹, characteristic of O-H bond stretching vibrations; in various infrared spectra, 2927 cm⁻¹... -1 and 1645cm -1 These correspond to the C-H2 stretching vibration and the C=O stretching vibration, respectively. Compared with YSFT, the intensity of the relevant characteristic absorption peak in YRSF is reduced, while the intensity of the 2927 cm⁻¹ peak in YSCU, YSQU, and YSPP is reduced. -1 The absorption peak intensity also decreased, indicating that the preparation process of each nanocomposite disrupted some intermolecular hydrogen bonds and ordered structures, thereby promoting the transformation of the system from ordered to amorphous structure, improving the dispersibility of starch molecules and enhancing the uniformity of polyphenol compound binding.

[0063] (2) Crystal structure characteristics The crystallographic properties of YRSF, YSFT, and YS samples were determined using X-ray diffraction (Cu target, Kα rays). Samples were placed in an environment with 100% relative humidity for 24 hours before testing. The X-ray diffraction parameters were: 15 mA current; 40 kV operating voltage; scanning speed 10° / min; 2θ range 4.00°~40.00°; and a scanning step size of 0.02° (2θ).

[0064] XRD diffraction pattern as follows Figure 2 As shown, YS exhibits single diffraction peaks at 15.3° and 23.2° (2θ), as well as a double peak at approximately 17°, indicating a typical A-type crystal structure. YRSF and YSFT show characteristic diffraction peaks at 13° and 20° (2θ), indicating the formation of a V-type inclusion structure. YSCU, YSQU, and YSPP also show characteristic diffraction peaks around 13° and 20° (2θ), indicating that YSCU, YSQU, and YSPP also form V-type inclusion structures.

[0065] (3) Particle size distribution Take 0.2 g each of YRSF, YSFT, YSCU, YSQU, and YSPP samples, add 10 mL of distilled water, and disperse using ultrasound for 2 min. Determine the particle size distribution of the samples using a laser nanoparticle size analyzer. The measurement conditions were: temperature 25℃, starch refractive index 1.53, and absorbance 0.01.

[0066] like Figure 3 As shown, the average particle size of YRSF is approximately 165 nm, which is much lower than that of YSFT, indicating that YRSF has better structural stability and dispersion uniformity. The average particle size of YSCU is approximately 75 nm, the average particle size of YSQU is approximately 125 nm, and the average particle size of YSPP is approximately 150 nm, indicating that all three also have good structural stability and dispersion uniformity.

[0067] (4) Different digestible components of starch: Porcine pancreatic α-amylase (0.75 g, 12 U / mg) was suspended in 30 mL of sodium acetate buffer (0.1 M, pH 5.2), shaken at 37 °C for 30 min, then centrifuged at 1500 g for 10 min. The supernatant was collected and 459 U of amyloglucosidase was added. The mixture was then used as the working enzyme solution.

[0068] 0.2 g each of YRSF, YSFT, and YS samples were dispersed in 20 mL of sodium acetate buffer (0.1 M, pH 5.2), gelatinized in boiling water for 30 min, and then cooled to 37 °C. 5 mL of working enzyme solution was added to each sample, and enzymatic hydrolysis was performed in a shaker water bath at 37 °C and 160 rpm. 0.5 mL samples were taken at 0, 20, 40, 60, 80, 100, and 120 min, and 4 mL of 85% v / v ethanol was immediately added to terminate the enzyme reaction. The samples were then centrifuged at 4000 g for 2 min. The glucose content in the supernatant was then determined using a GOPOD kit. Based on the glucose release curve, the contents of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS), as well as the hydrolysis rate, were calculated using the following formula.

[0069] RDS(%) = (G20 - FG) × 0.9; SDS(%) = (G120 - G20) × 0.9; RS(%) = 100 - (RDS + SDS); Wherein, G20 and G120 represent the amount of glucose released after 20 min and 120 min of enzymatic hydrolysis, respectively, and FG is the free glucose content in starch.

[0070] The results are as follows Figure 4As shown, the RS ratio in YRSF prepared by this invention (57.68%) is significantly higher than that in YSFT (49.88%), and it has a significantly reduced enzymatic hydrolysis rate. This indicates that the preparation method provided by this invention can improve the RS ratio of the obtained complex. It also shows that the YRSF prepared by this invention has a high resistance to enzymatic hydrolysis, which is beneficial to reducing its decomposition during digestion, and thus may have the potential to reduce postprandial blood glucose response.

[0071] The contents of RDS, SDS, and RS in YSCU, YSQU, and YSPP were determined using the same method, and the results are as follows: Figure 5 As shown, the proportion of RS was highest in YSCU, while it was lower in YSQU and YSPP than in YSCU. This may be related to the fact that the structure and physicochemical properties of quercetin and tea polyphenols are different from those of curcumin.

[0072] (5) Determination of composite rate Accurately weigh 100 mg each of YRSF, YSFT, YSCU, YSQU, and YSPP samples, and add them to separate 100 mL volumetric flasks. Add 1 mL of anhydrous ethanol and 9 mL of NaOH solution (1 mol / L) to each flask, mix well, and then heat in a boiling water bath for 10 min. After cooling, add water to the mark. Take 5 mL of the solution and add it to a 100 mL volumetric flask. Add 1 mL of glacial acetic acid solution (1 mol / L) and 2 mL of iodine reagent, and then add water to the mark. After zeroing the flask with a blank solution, measure the absorbance at 690 nm and calculate the recombination rate using the following formula.

[0073] CI (%) = (Control group absorbance - Sample absorbance) / Control group absorbance × 100% The results are as follows Figure 6 As shown, compared to YSFT, YRSF prepared by this invention has a higher composite rate, and the binding ratio of ferulic acid in the starch system is increased, indicating that the method of preparing YRSF by this invention can enhance the structural stability and functionality of the complex. The composite rates of YSCU, YSQU, and YSPP are lower than those of YRSF, which may be related to the fact that the properties of curcumin, quercetin, and tea polyphenols are different from those of ferulic acid.

[0074] Example 5 In this embodiment, the yam native starch (YS) and yam starch-ferulic acid nanocomposite (YRSF) prepared in Example 1, the yam starch + ferulic acid mixture (YSF) prepared in Comparative Example 2, and the yam-derived type III resistant starch (YRS) prepared in Comparative Example 3 were used as test samples to investigate the regulatory effects of the test samples on glucose and lipid metabolism in mice on a high-fat diet.

[0075] 1. Laboratory mice SPF-grade male C57BL / 6J mice, weighing 20–22 g, were housed under standard laboratory conditions (temperature 20–25°C, relative humidity 45%–55%) with free access to food and water. After one week of acclimatization, the mice were randomly divided into 5 groups (n = 5 mice / group) according to their weight. This study protocol was approved by the Animal Ethics and Welfare Committee (Approval No. ZXHK-DWLL-2025-0121). NC group: fed with regular feed; HFD group: fed a high-fat diet; YS group: high-fat diet containing 10% wt YS; YRSF group: high-fat diet containing 10% wt YRSF; YRS group: high-fat diet containing 10% wt YRS; YSF group: high-fat diet containing 10% wt YSF.

[0076] Mice in each group were given the above-mentioned feed and test samples, respectively, for a total of 12 weeks.

[0077] 2. Observation Indicators During the experimental observation period, the changes in body weight and food intake of mice in each group were recorded weekly, and the average weekly food intake of mice in each group was calculated on the last day of the experiment.

[0078] After 8 weeks of dietary intervention, an oral glucose tolerance test (OGTT) was performed: Mice were fasted for 14 hours in clean cages with free access to water. Glucose solution was administered orally by gavage at a dose of 2 g / kg body weight. Blood samples were collected from the tail tip at 0, 30, 60, 90, and 120 minutes after glucose administration, and blood glucose levels were measured using a glucometer to generate glucose response curves. The area under the curve (AUC) was calculated using the following formula: AUC = 0.25 × (Glucose 0min + Glucose 30min ) + 0.25 × (Glucose 30min +Glucose 60min ) + 0.25 × (Glucose 60min + Glucose 90min ) + 0.25 × (Glucose 90min +Glucose 120min ). Among them, Glucose 0min Glucose 30min Glucose 60min Glucose 90min Glucose 120minThese represent blood glucose levels at 0, 30, 60, 90, and 120 minutes after glucose administration.

[0079] Three days after the oral glucose tolerance test (OGTT), an insulin tolerance test (ITT) was performed: mice in all groups fasted for 5 hours under the same conditions and were injected intraperitoneally with insulin at a dose of 0.5 U / kg body weight. Blood samples were collected from the tail tip at 0, 30, 60, 90, and 120 minutes after insulin injection, and fasting blood glucose levels (FBG (mmol / L)) were measured using a glucometer. Insulin response curves were plotted, and the area under the curve (AUC) was calculated. Fasting serum insulin (FBI (pg / mL)) was measured using a commercial ELISA kit, and the insulin sensitivity index (QUICKI) and insulin resistance index (HOMA-IR) were calculated.

[0080] After the final day of the experiment, mice were fasted for 12 hours, anesthetized, and retroorbital blood was collected. Serum was collected after centrifugation at 3000 rpm for 10 minutes at 4°C. Mice were euthanized, and scapular fat, epididymal fat, liver, pancreas, kidneys, small intestine, and colon were collected. The livers were weighed. Each tissue was divided into two parts using sterile surgical scissors: one part was fixed with 4% paraformaldehyde for histological analysis, and the other part was frozen in liquid nitrogen and stored at -80°C for molecular detection. The contents of the small intestine and cecum were collected separately, frozen in liquid nitrogen, and stored at -80°C for analysis.

[0081] The levels of inflammatory factors TNF-α and IL-6 in mouse serum and liver were determined using an ELISA kit. The levels of TG, TC, HDL-C, and LDL-C in mouse serum were measured using a fully automated biochemical analyzer.

[0082] Liver tissue fixed in 4% paraformaldehyde was stained with Oil Red O, and colon tissue fixed in 4% paraformaldehyde was stained with H&E to assess mucosal structure and goblet cell distribution.

[0083] The content of perirenal white fat, epididymal white fat, and scapular brown fat was measured.

[0084] Genomic DNA was isolated from all samples, and three mice were randomly selected from each group for sequencing. Conserved regions were amplified using PCR with sequencing adapters added. The products were purified, quantified, and normalized for library construction. Sequencing was performed on an Illumina NovaSeq 6000 platform (Illumina, San Diego, USA). Raw data underwent quality control on the BMKCloud platform (Biomarker Technologies, Beijing, China), including pruning and primer removal. High-quality reads were then denoised, merged, and chimeras were filtered using the DADA2 plugin in QIIME2. Downstream analyses included ASV / OTU clustering, diversity assessment (α- and β-diversity), differential abundance testing, correlation analysis, and functional prediction.

[0085] 3. Results The curves showing the change in body weight of mice in each group are as follows: Figure 7 As shown in Figure A, the final weight is as follows Figure 7 As shown in Figure B, the average food intake during the experiment was as follows: Figure 7 As shown in Figure C, with no significant difference in food intake among the groups, the body weight of all groups increased over time. The body weight of the HFD group mice continued to increase throughout the feeding cycle, ultimately reaching a significantly higher body weight than the NC group, demonstrating that the model can stably induce body weight gain. Adding the YRSF of this invention to the high-fat diet effectively suppressed the trend of body weight gain in mice, resulting in a final body weight significantly lower than the HFD group, lower than the YS and YSF groups, and close to the level of the NC group on a normal diet. This indicates that YRSF can effectively counteract the body weight gain induced by HFD. In contrast, adding YS directly to the high-fat diet resulted in a more significant increase in body weight, with no significant difference from the HFD group, and did not show an inhibitory effect on obesity development. These results indicate that simply supplementing with natural starches, which are refined carbohydrates, cannot improve body weight gain under high-fat conditions; on the contrary, it may further promote its development. Supplementing with the YRSF of this invention can effectively improve this problem.

[0086] like Figure 7 As shown in Figures D to G, under the same feeding conditions, the liver mass, perirenal white adipose tissue (pWAT) mass, and epididymal white adipose tissue (eWAT) mass of mice given the YRSF of this invention were all lower than those in the HFD group, indicating that the complex can reduce adipose tissue deposition and improve fat accumulation without affecting appetite. Since the food intake of mice in each group was basically the same, this further indicates that the effect was not caused by differences in food intake.

[0087] Blood glucose related indicators such as Figure 8As shown: Although the area under the blood glucose curve in the HFD group did not show significant abnormalities, compared with the NC group, a high-fat diet increased FBI and HOMA-IR and decreased QUICKI in mice, indicating that the HFD group was already in the early stage of metabolic abnormality with insulin compensation; adding YS to the diet increased FBG, FBI, and HOMA-IR and decreased QUICKI in mice; compared with the HFD group, YRSF intervention significantly improved the increase in FBI and HOMA-IR and decrease in QUICKI caused by a high-fat diet, indicating that YRSF effectively improved insulin resistance induced by a high-fat diet, while YRS and YSF had no significant effect on decreasing FBI and HOMA-IR and increasing QUICKI.

[0088] Blood lipid-related indicators such as Figure 9 As shown in Figures A through D, mice in the HFD group exhibited significantly elevated serum TC, TG, and LDL-C levels, indicating abnormal lipid metabolism and demonstrating that a high-fat diet successfully induced a hyperlipidemia model. Compared to the HFD group, administration of YS further significantly increased serum TC levels, while the YRSF group showed significantly decreased TG, TC, and LDL-C levels, indicating that YRSF can alleviate HFD-induced hyperlipidemia. Furthermore, the significant reduction in TG, TC, and LDL-C by YRSF suggests that overall cholesterol and lipoprotein secretion were inhibited, thereby reducing the demand for HDL from reverse cholesterol transport, resulting in a passive decrease in HDL-C. This change is an adaptive regulation following the improvement in overall lipid metabolism, consistent with increased cholesterol efflux and bile acid synthesis.

[0089] Mouse liver staining results as follows Figure 9 As shown in Figure E, H&E staining results revealed an increase in the number and volume of fat vacuoles in the liver of the HFD group, while the liver tissue structure of the YS group showed significant disorder, with irregular hepatocyte arrangement and nuclear compression and deformation. Simultaneously, Oil Red O staining results also showed a more significant accumulation of fat vacuoles within hepatocytes in the YS group; these vacuoles appeared bright red under Oil Red O staining, indicating intensified lipid accumulation. In contrast, the liver pathological changes in the YRSF group were significantly improved, with a marked inhibition of the increase in liver fat vacuole volume, a degree of protection of hepatocyte structure, and a regulation of the liver pathological state.

[0090] Figure 10 The results showed that, compared to the NC group, the HFD group mice had significantly higher serum levels of LPS and TNF-α, indicating enhanced systemic inflammatory response. Simultaneously, the levels of hepatic inflammatory factors TNF-α and IL-6 were also significantly increased, indicating local inflammatory activation. Compared to the HFD group, YRSF significantly reduced the levels of inflammatory factors TNF-α and IL-6 in mouse serum and liver.

[0091] A healthy gut acts as a strong barrier, protecting the body from harmful microorganisms and toxins while promoting nutrient absorption and maintaining a balanced gut microbiota. Figure 11 As shown, colonic H&E staining revealed significant structural changes in the HFD group, characterized by abnormal crypt morphology and a reduction or absence of goblet cells in the mucosa and submucosa. These changes further exacerbated inflammatory cell infiltration and led to thinning of the intestinal wall muscular layer, thereby weakening the integrity of the colonic structure. With the deterioration of barrier function, serum lipopolysaccharide (LPS) levels increased, which may trigger the release of pro-inflammatory cytokines (such as TNF-α and IL-6) by immune cells, leading to chronic low-grade inflammation. Figure 10 The results were consistent. YRSF intervention effectively restored the number and function of goblet cells, reduced inflammatory cell infiltration, and improved the integrity of the muscular layer; furthermore, YRSF promoted the normal synthesis and secretion of colonic mucus, thereby helping to maintain intestinal barrier function and regulate immune response.

[0092] In α diversity analysis ( Figure 12 (Figures A-D in the original text) Compared to the NC group, the HFD group showed significantly lower Shannon, ACE, and Chao1 indices, indicating that a high-fat diet reduced the richness and evenness of the gut microbiota. YRSF intervention partially restored gut microbiota richness (ACE and Chao1) but did not significantly improve diversity (Shannon index), suggesting that its main effect was to increase the abundance of rare taxa rather than alter the evenness of dominant taxa. In the β-diversity analysis (… Figure 12 Figures E to G in the table show that HFD significantly altered the gut microbiota structure, leading to a clear separation from the NC group, indicating that a high-fat diet induced significant changes in microbial composition. Although YRSF intervention partially altered the community structure, it did not lead to substantial convergence to the NC group, suggesting that its effect on restoring the overall microbial community composition was limited.

[0093] At the gate level ( Figure 12 (See Figure H in the diagram). The gut microbiota of mice is mainly composed of Firmicutes and Bacteroidetes. Compared with the NC group, the F / B ratio in the HFD group was significantly reduced ( Figure 12 The L-plot in the figure suggests that a high-fat diet may disrupt gut microbiota homeostasis. (Genetic level analysis results) Figure 12 Figure I in the diagram) and LEfSe analysis results ( Figure 13The study revealed the most significant microbial alterations in the YRSF group, characterized by the enrichment of beneficial genera such as Akkermania and Oscillatoria, which are closely associated with short-chain fatty acid production, mucosal barrier repair, and inflammation regulation. In contrast, the HFD group was enriched in genera associated with inflammation and barrier dysfunction, including Helicobacter pylori, Campylobacter, Bifidobacterium, and Desulfovibrio. The YRS group showed a significant increase in the number of the probiotic Bifidobacterium, while the YS group was enriched in genera involved in polysaccharide degradation. On the other hand, the YSF group was enriched in butyrate-producing genera such as Faecalibacterium and Brukinsa, suggesting that its physiological benefits may be achieved through enhanced butyrate production and subsequent improvement of the gut microenvironment. Significant differences in microbial composition existed among the groups. Compared to the HFD group, the relative abundance of Akkermania and Rhodotorula buergeriana was significantly increased in the YRSF group. These genera are widely recognized for their roles in maintaining mucosal barrier integrity, producing short-chain fatty acids, and regulating inflammation, suggesting that they may improve host metabolic phenotypes through YRSF and play a key role in its interventional effects.

[0094] Example 6 In this embodiment, the yam starch-curcumin nanocomposite (YSCU) prepared in Example 2, the yam starch-quercetin nanocomposite (YSQU) prepared in Example 3, and the yam starch-tea polyphenol nanocomposite (YSPP) prepared in Example 4 were used as test samples to investigate the effects of the test samples on the body shape, weight and sugar metabolism of fruit flies.

[0095] 1. Preparation of culture medium 1.1 Normal culture medium Prepare the following formula per 100mL: 1g agar, 8g yeast, 4g yeast extract, 5.1g sucrose, and distilled water to 100mL.

[0096] After thoroughly mixing the above ingredients, heat them in a microwave oven on medium-high heat for 3 minutes each time, for a total of 2 heating cycles, until the culture medium reaches a slight boiling state and the agar is completely dissolved. Stir occasionally during heating to avoid localized overheating or clumping.

[0097] After the culture medium is heated, allow it to cool to approximately 60°C. Add 600 μL of propionic acid and 1 mL of antibiotic solution, and stir thoroughly. Then pour the culture medium into fruit fly culture tubes until the liquid level is approximately 1.5 cm. Allow it to cool and solidify naturally before use.

[0098] The preparation method of the antibiotic solution is as follows: Weigh 5.1g of methyl 4-hydroxybenzoate, dissolve it in 50mL of anhydrous ethanol, and store it at 4℃ protected from light for later use.

[0099] 1.2 High-glucose culture medium Prepare per 100mL as follows: 1g agar, 8g yeast, 4g yeast extract, 48g sucrose, add distilled water to 100mL.

[0100] After thoroughly mixing the above ingredients, place them in a microwave oven and heat for 3 minutes each time on medium-high heat, for a total of 2 heating cycles, until the culture medium reaches a slight boiling state and the agar is completely dissolved. Stir occasionally during heating to prevent localized overheating or clumping.

[0101] After the culture medium is heated, let it cool to about 60°C, add 600 μL of propionic acid and 1 mL of antibiotic solution, mix thoroughly, dispense into fruit fly culture bottles, and let cool and solidify naturally for later use.

[0102] 1.3 Starch-High Sugar Medium Add an extra 24g of starch to every 100mL of high-sugar culture medium formulation; the remaining ingredients and preparation steps are the same as for high-sugar culture medium.

[0103] 1.4 Complex-High Glucose Medium For every 100 mL of high-glucose culture medium, add an additional 24 g of YSCU, YSQU, or YSPP. The remaining ingredients and preparation steps are the same as for the high-glucose culture medium.

[0104] 2. Experimental Methods 2.1 Grouping and administration of Drosophila Adult fruit flies of the same age obtained from free mating were randomly divided into 6 groups: normal control group (NC), high sugar model group (HSD), yam starch group (YS), yam starch-curcumin nanocomposite group (YSCU), yam starch-quercetin nanocomposite group (YSQU), and yam starch-tea polyphenol nanocomposite PP group (YSPP). Each group contained approximately 120 fruit flies.

[0105] Drosophila in the NC group were fed with normal culture medium; Drosophila in the HSD group were fed with high-glucose culture medium to establish a high-glucose-induced metabolic disorder model. Drosophila in the YS, YSPP, YSCU, and YSQU groups were fed with starch-high-glucose culture medium and their corresponding complex-high-glucose culture medium, respectively, to evaluate the ameliorative effect of different treatments on high-glucose-induced metabolic abnormalities.

[0106] All fruit flies were reared at 25°C under a 12-hour light / dark cycle for 7 consecutive days. The culture medium was changed every 3 days during the experiment. After the intervention, the fruit flies were subjected to further experimental testing on day 8, then euthanized under CO2 anesthesia and stored at -80°C for later use.

[0107] 2.2 Fruit fly weight determination Ten euthanized fruit flies from each group were placed in centrifuge tubes. The fruit flies from each group were weighed using an analytical balance, with six biological replicates per group. After weighing, the fruit flies from each group were observed under a microscope to examine their morphology and size, and photographs were taken.

[0108] 2.3 Determination of biochemical indicators in fruit flies The entire procedure was performed on ice. Drosophila were placed in 1.5 mL centrifuge tubes, and their thoraxes were punctured to release hemolymph. The resulting sample was collected in pre-chilled 2 mL centrifuge tubes. The collected hemolymph sample was centrifuged at 15,000 × g for 15 min at 4 °C, and the supernatant was collected. Then, 1 μL of the supernatant was added to 24 μL of PBS buffer for a 25-fold dilution. The diluted sample was incubated in a 70 °C metal bath for 5 min to inactivate endogenous enzymes, followed by centrifugation at 14,000 × g for 15 min. The supernatant was used for detection. 7 μL of the treated supernatant was mixed with 700 μL of the detection working solution and reacted at 37 °C for 30 min. After the reaction, the absorbance was measured at 505 nm using a microplate reader or spectrophotometer. A trehalase standard control group was also set up. Trehalase stock solution was diluted 100-fold and added to the reaction system at 20 μL per well to verify the specificity and reliability of the detection method.

[0109] 3. Results 3.1 Body shape and weight like Figure 14 As shown, compared with the normal control group (NC), the high-sugar diet (HSD) significantly altered the body shape of fruit flies. The fruit flies in the model group were generally smaller and had reduced abdominal fullness, suggesting that the high-sugar diet adversely affected the growth, development, and energy metabolism of fruit flies. Compared with the HSD group, the body shape of fruit flies treated with yam starch (YS) did not improve significantly, while the body shape of fruit flies treated with yam starch-polyphenol nanocomposites (YSPP, YSCU, and YSQU) all showed significant changes, with significantly larger bodies, increased abdominal fullness, and an overall morphology closer to the normal control group.

[0110] Fruit fly weight measurement results (e.g.) Figure 15 As shown in the figure, the body shape changes were consistent with those of the NC group. Compared with the NC group, the body weight of the fruit flies in the HSD group was significantly reduced (as shown in the figure). p <0.0001), while the body weight of fruit flies in the YSPP, YSCU, and YSQU groups was significantly higher than that in the HSD group ( p The value <0.0001 indicates that the yam starch-polyphenol nanocomposite can effectively improve the weight loss of fruit flies induced by a high-sugar diet, and the complexes modified with different polyphenols all showed good intervention effects.

[0111] 3.2 Biochemical Indicators like Figure 16As shown, compared with the normal control group (NC), the high-sugar diet (HSD) significantly increased all carbohydrate indicators. However, the intervention of the three complexes YSPP, YSCU, and YSQU exhibited a unique regulatory pattern: they significantly reduced the excessively high blood glucose and total glucose levels induced by HSD, while precisely maintaining trehalose levels at an intermediate state—lower than the HSD group but significantly higher than the NC group. Trehalose is a typical stress metabolite, mainly derived from endogenous metabolic synthesis, and is the main circulating glucose form in Drosophila. Its metabolism is closely related to fat body function, and changes in its level reflect the regulation of glucose homeostasis in the body. The results of this experiment demonstrate that these complexes do not simply inhibit glucose metabolism, but may synergistically regulate glucose and lipid metabolism by preferentially regulating trehalose, an important stress and energy buffer, to help the body adapt to metabolic stress.

[0112] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a yam starch-polyphenol nanocomposite, characterized in that, Specifically, the following steps are included: S1. Peel and homogenize the yam, then sieve it. Let the filtrate stand, discard the supernatant, and wash the precipitate repeatedly with distilled water until the supernatant is colorless. Dry the obtained white starch layer, pulverize it, and sieve it to obtain yam raw starch. S2. The yam starch is gelatinized with water, added to anhydrous ethanol, and stirred under high-speed shear conditions of 2000~15000 rpm. Then, a polyphenol compound is added, and stirring is continued under high-speed shear conditions of 2000~15000 rpm. The resulting precipitate is collected, washed with an ethanol aqueous solution, and dried to obtain the yam starch-polyphenol nanocomposite.

2. The preparation method according to claim 1, characterized in that, The polyphenolic compounds include ferulic acid, curcumin, quercetin, and tea polyphenols.

3. The preparation method according to claim 1 or 2, characterized in that, The homogenized slurry described in S1 is then passed through a 100-mesh sieve; and / or The settling time described in S1 is 10-15 hours, and the temperature is 2-6℃; and / or The drying temperature described in S1 is 35~45℃; and / or The material described in S1 is pulverized and then passed through a 200-mesh sieve.

4. The preparation method according to claim 3, characterized in that, The settling time described in S1 is 12 hours, and the temperature is 4°C; and / or The drying temperature described in S1 is 40°C.

5. The preparation method according to claim 1 or 2, characterized in that, The gelatinization operation described in S2 is as follows: dispersing the yam starch in distilled water and stirring at 95-98°C for 20-40 minutes; and / or The mass of the polyphenolic compound in S2 is 2% to 12% of the mass of the yam starch; and / or Before adding the polyphenol compound to S2, the stirring time under the high-speed shear condition is 4-6 minutes; after adding the polyphenol compound, the stirring time under the high-speed shear condition continues for 8-12 minutes; and / or The concentration of the ethanol-water solution described in S2 is 70%~90% v / v; and / or The drying temperature described in S2 is 50~70℃.

6. The preparation method according to claim 5, characterized in that, Disperse 1-10g of the yam starch in 100-200mL of distilled water; and / or The mass of the polyphenol compound in S2 is 10% of the mass of the yam starch; and / or The high-speed shearing speed in S2 is 10000 rpm. Before adding the polyphenol compound, the stirring time under the high-speed shearing condition is 5 minutes. After adding the polyphenol compound, the stirring time under the high-speed shearing condition continues for 10 minutes; and / or The concentration of the ethanol-water solution described in S2 is 80% v / v; and / or The drying temperature described in S2 is 60°C.

7. A yam starch-polyphenol nanocomposite, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 6.

8. The application of the yam starch-polyphenol nanocomposite according to claim 7, characterized in that, include: Its application in the preparation of drugs for the prevention and treatment of obesity; Applications in the preparation of anti-inflammatory drugs; Its application in the preparation of drugs for the prevention and treatment of hyperglycemia; Applications in the preparation of health foods that help control body fat; Applications in the preparation of health food products that help maintain healthy blood lipid levels; Applications in the preparation of health foods that help maintain healthy blood sugar levels.

9. A product for improving glucose and lipid metabolism, characterized in that, Its active ingredients include the yam starch-polyphenol nanocomposite as described in claim 7. The product is a medicine for preventing and treating obesity, or a health food that helps control body fat, helps maintain healthy blood lipid levels, and / or helps maintain healthy blood sugar levels.

10. An anti-inflammatory drug, characterized in that, Its active ingredients include the yam starch-polyphenol nanocomposite as described in claim 7, wherein the polyphenol compound is ferulic acid.

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