A soluble dietary fiber composition, its preparation method and application

Abstract

This invention provides a soluble dietary fiber composition, its preparation method, and its application. Upon entering the colon, the ester bonds in the alanine-modified pectin rapidly degrade, releasing some chlorogenic acid, stimulating the secretion of anorexia nervosa hormones, reducing appetite, and decreasing calorie intake; the remaining amide bond network slowly degrades, achieving a slow and continuous release of chlorogenic acid. Lutein scavenge free radicals generated from fat breakdown, reducing oxidative damage to L cells. Galactomannan and the alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex synergistically increase the butyrate / propionic acid molar ratio: propionic acid enhances satiety through intestinal gluconeogenesis, while butyrate stimulates the secretion of GLP-1 / PYY, achieving endogenous appetite suppression. Galactomannan absorbs water to form a lubricating gel, softening stool and increasing stool volume; the ternary complex degrades to produce short-chain fatty acids, optimizing the intestinal microenvironment and enhancing gastrointestinal motility; both synergistically improve constipation.

Description

Technical Field

[0001] This invention specifically relates to a soluble dietary fiber composition, its preparation method, and its application. Background Technology

[0002] Obesity not only affects body shape and quality of life, but is also a significant risk factor for type 2 diabetes, hypertension, cardiovascular disease, non-alcoholic fatty liver disease, and even various cancers, placing a heavy burden on individual health and the national healthcare system. Current weight loss interventions have significant shortcomings: GLP-1 drugs, such as semaglutide, are effective, but they are expensive, have a high rebound rate after discontinuation, and about 30-50% of users experience gastrointestinal side effects such as constipation; commercially available meal replacements have limited functions, either only providing a temporary feeling of fullness or only targeting bowel movements, making it difficult to simultaneously address weight loss and gut health.

[0003] Dietary fiber refers to polysaccharides that cannot be digested and absorbed by human digestive enzymes. Based on their solubility in water, they can be divided into two main categories: soluble dietary fiber and insoluble dietary fiber. Soluble dietary fiber can dissolve in water to form colloids or gels, and mainly includes pectin, beta-glucan, galactomannan, konjac glucomannan, inulin, and fructooligosaccharides. Numerous nutritional and clinical studies have shown that soluble dietary fiber has the most significant effects on weight management and metabolic health. However, most dietary fiber products currently on the market are simple physical mixtures of several dietary fibers, and their functions are relatively limited.

[0004] Polyphenolic compounds are secondary metabolites with multi-phenolic structures found in plant tissues and organs. They mainly exert their fat-reducing effects by regulating fat production and metabolism, liver function, glucose metabolism, and gut microbiota. However, polyphenolic compounds have poor water solubility, are unstable under light and heat, and are easily degraded in the gastrointestinal tract, resulting in low oral bioavailability.

[0005] Therefore, there is an urgent clinical need and a broad market prospect for developing a soluble dietary fiber composition that can effectively reduce fat, improve constipation, and have synergistic effects among its components. Summary of the Invention

[0006] One of the objectives of this invention is to provide a soluble dietary fiber composition to solve the above-mentioned technical problems.

[0007] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows: A soluble dietary fiber composition, by weight, comprises the following components: 50-70 parts galactomannan, 20-40 parts alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex, and 3-6 parts lutein.

[0008] As a further improvement, the preparation method of the alanine-modified pectin-dextran-modified protein-chlorogenic acid ternary complex is as follows: S1. Dissolve alanine-modified pectin in a tert-butanol / water mixed solvent at a solid-liquid ratio of 1g:75mL. Stir until completely dissolved, then add dextran-modified protein-encapsulated chlorogenic acid, add 3Å molecular sieve, maintain the water activity of the system at 0.3~0.5, add lipase Novozym 435, and stir the reaction at 45~50℃ and 200rpm for 6~8h under a nitrogen atmosphere, in the dark. S2. After the reaction is complete, the solution is filtered through a 100-mesh sieve. The filtrate is slowly added to an excess of anhydrous ethanol at 4°C and allowed to stand at 4°C for 2 hours. After centrifugation and washing, the precipitate is dialyzed through a dialysis bag with a cutoff of 50 kDa for 24-36 hours. The dialysate is then freeze-dried to obtain alanine-modified pectin-dextran-modified protein-chlorogenic acid ternary complex.

[0009] As a further improvement, the mass ratio of alanine-modified pectin to dextran-modified protein-encapsulated chlorogenic acid is 1:0.2~0.4; the amount of lipase Novozym 435 added is 5~10% of the total mass of alanine-modified pectin and dextran-modified protein-encapsulated chlorogenic acid.

[0010] As a further improvement, the preparation method of the alanine-modified pectin is as follows: S1. Mix alanine solution and papain solution at a volume ratio of 2~2.5:1 to obtain a mixed solution; add pectin solution to the mixed solution at a volume ratio of 1~1.2:1 at 400 rpm, then add anhydrous ethanol, purge air with nitrogen, and then seal and stir at -15℃ and 400 rpm for 12~24 h. S2. After the reaction is complete, add excess anhydrous ethanol to precipitate the product. Centrifuge and collect the precipitate. Resuspend the precipitate in 15wt% trichloroacetic acid solution and stir for 15 min. Centrifuge again and discard the supernatant. Dialyze the product in deionized water at 4℃ using a dialysis bag with a molecular weight cutoff of 30 kDa. After freeze-drying, alanine-modified pectin is obtained.

[0011] As a further improvement, the method for preparing the papain solution is as follows: Under a nitrogen atmosphere, papain is dissolved in 0.05M phosphate buffer at pH 7.0 at a solid-liquid ratio of 1g:90mL, stirred for 30min in an ice bath at 0-5℃, then 0.4M L-cysteine ​​hydrochloride solution and ethylenediaminetetraacetic acid are added, and stirring is continued for 10min to obtain the papain solution; the mass ratio of L-cysteine ​​hydrochloride to papain is 0.7-1.0:1; the amount of ethylenediaminetetraacetic acid added is 2-4% of the mass of papain.

[0012] As a further improvement, the preparation method of the dextran-modified protein containing chlorogenic acid is as follows: S1. Dissolve dextran-modified protein in 50 mL of distilled water at a solid-liquid ratio of 1 g: 50 mL, stir well, and adjust the pH to 8.0-9.0 to obtain a dextran-modified protein dispersion; Under a nitrogen atmosphere and in the dark, dissolve chlorogenic acid in distilled water at a solid-liquid ratio of 1 g: 200 mL, adjust the pH to 9.0, and filter through a 0.22 μm filter membrane to obtain a chlorogenic acid solution; Under a nitrogen atmosphere and in the dark, chlorogenic acid solution was added to the dextran-modified protein dispersion at a volume ratio of 1:1 and stirred continuously at room temperature for 4-6 hours. After the reaction was completed, the mixture was dialyzed and freeze-dried to obtain dextran-modified protein containing chlorogenic acid.

[0013] As a further improvement, the preparation method of the dextran-modified protein is as follows: Whey protein isolate was dissolved in deionized water, the pH was adjusted to 8.0, and the mixture was stirred at room temperature until completely dissolved. Dextran was then added and stirred for 10 minutes. The mixture was then ultrasonically stirred at 300W and 70℃ for 60-80 minutes. After the reaction was completed, the mixture was quickly placed in an ice bath to stop the reaction. After dialyzing through a 50kDa molecular weight cutoff dialysis bag, the retentate was collected and freeze-dried to obtain dextran-modified protein.

[0014] As a further improvement, the mass ratio of whey protein isolate to dextran is 1:0.75~0.85.

[0015] Another object of the present invention is to provide a method for preparing a soluble dietary fiber composition, comprising the following steps: taking galactomannan, alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex and lutein in proportion, mixing them, and passing them through an 80-mesh sieve to obtain a soluble dietary fiber composition.

[0016] Another object of the present invention is to provide an application of a soluble dietary fiber composition in the preparation of functional foods or medicines for weight loss, fat reduction, prevention or relief of constipation.

[0017] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows: 1. Using alanine to modify pectin results in amide bonds that are less sensitive to pectinase than ester bonds in pectin. After entering the colon, the soluble dietary fiber composition rapidly degrades the ester bonds in the pectin network, releasing some chlorogenic acid and stimulating colonic L cells to secrete anorexia hormones, including glucagon-like peptide-1 (GLP-1) and peptide tyrosine-tyrosine (PYY), thus achieving endogenous appetite suppression. Simultaneously, pectin absorbs water and swells in the body, enhancing satiety. The two work synergistically to reduce calorie intake. The remaining pectin network, mainly composed of amide bonds, degrades slowly and is released at a relatively stable rate, prolonging the overall duration of action and thus achieving a sustained effect of suppressing appetite and reducing calorie intake. Meanwhile, lutein, as a fat-soluble antioxidant, is released simultaneously during the covalent network degradation process, clearing excess free radicals generated by fat breakdown during weight loss, protecting colonic L cells from oxidative damage, and maintaining their long-term ability to secrete GLP-1 / PYY.

[0018] 2. Co-fermentation of alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex with galactomannan: After entering the colon, galactomannan is rapidly fermented by the gut microbiota to produce a high concentration of butyric acid; the alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex, due to amidation modification, degrades slowly and continuously releases propionic acid and acetic acid; the two work synergistically to increase the butyric acid / propionic acid molar ratio, propionic acid first enhances satiety through intestinal gluconeogenesis, and the high proportion of butyric acid specifically activates colonic L cells to secrete GLP-1 and PYY, thereby achieving endogenous appetite suppression.

[0019] 3. After entering the colon, galactomannan efficiently absorbs water to form a lubricating gel, which can quickly soften hard stools and increase stool volume. At the same time, it rapidly proliferates beneficial bacteria such as Bifidobacteria, achieving an early laxative effect. The short-chain fatty acids produced by the slow degradation of the alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex can prolong the stimulation time of colonic L cells, optimize the intestinal microenvironment, and enhance intestinal peristalsis. The two work synergistically to increase the frequency of defecation and restore constipated stools to normal stools. Attached Figure Description

[0020] Figure 1 Infrared spectra of citrus pectin before and after modification with alanine. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or manufacturer's conditions shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0022] Example 1: A method for preparing a soluble dietary fiber composition, comprising the following steps: 1. Under a nitrogen atmosphere, dissolve 2g of papain in 180mL of 0.05mol / L phosphate buffer (pH 7.0), stir at 200rpm for 30min in an ice bath at 0℃, add 25mL of 0.4mol / L L-cysteine ​​hydrochloride solution and 40mg of ethylenediaminetetraacetic acid, and continue stirring for 10min to obtain papain solution.

[0023] 2. Dissolve 1.3g of alanine in 100mL of 0.2mol / L phosphate buffer (pH 7.0) to obtain an alanine solution; mix the alanine solution with 50mL of papain solution to obtain a mixed solution; dissolve 5g of citrus pectin (D-galacturonic acid content ≥74%, degree of esterification 62~75%) in 150mL of 0.2mol / L phosphate buffer (pH 7.0) to obtain a pectin solution; add the pectin solution to the mixed solution while stirring at 400rpm, add 100mL of anhydrous ethanol, continue to purge with nitrogen for 15min to remove air, and then seal and stir at -15℃ and 400rpm for 12h.

[0024] 3. After the reaction was complete, 800 mL of anhydrous ethanol was added for precipitation. The mixture was then centrifuged at 4000 rpm for 5 min, and the precipitate was collected. The precipitate was then resuspended in 100 mL of 15 wt% trichloroacetic acid solution for 15 min. After centrifugation at 8000 rpm for 10 min, the supernatant was discarded. The precipitate was dialyzed through a dialysis bag with a molecular weight cutoff of 30 kDa in deionized water at 4 °C. After freeze-drying at -50 °C and 0.1 mbar, alanine-modified pectin was obtained. Infrared spectroscopy was performed on the citrus pectin before and after alanine modification. The results are shown below. Figure 1 As shown, a represents the infrared spectrum of citrus pectin before alanine modification; b represents the infrared spectrum of citrus pectin after alanine modification; in the infrared spectrum of alanine-modified pectin, 1739 cm⁻¹... -1 and 1670 cm -1 A significantly enhanced absorption peak appeared at 678 cm⁻¹, corresponding to the CO stretching vibrations of the ester (-COO-) and amide (-CONH-) groups, respectively; simultaneously, a peak was observed at 678 cm⁻¹. -1 The presence of NH plane bending vibration further confirms the covalent bond between alanine and pectin.

[0025] 4. Dissolve 2g of whey protein isolate in 100mL of deionized water, adjust the pH to 8.0 with 0.1mol / L NaOH, stir at 300rpm for 30min at room temperature until completely dissolved, add 1.5g of oat β-glucan (average molecular weight 40kDa), stir to dissolve for 10min, and react at 300W and 70℃ for 60min, maintaining continuous stirring at 200rpm during the reaction. After the reaction is completed, quickly cool the reaction solution to 4℃ in an ice bath to terminate the reaction. Dialyze through a dialysis bag with a molecular weight cutoff of 50kDa for 24h, collect the retentate, freeze-dry it, and obtain the glucan-grafted modified protein; oat β-glucan can also be one or more of galacto-oligosaccharides, polydextrose, or stachyose.

[0026] 5. Dissolve 1.0 g of dextran-modified protein in 50 mL of distilled water, stir at 4000 rpm until uniformly dispersed, and adjust the pH to 8.0 with 0.1 mol / L NaOH to obtain a dextran-modified protein dispersion. Under nitrogen atmosphere and in the dark, dissolve 0.25 g of chlorogenic acid in 50 mL of distilled water, adjust the pH to 9.0 with 0.1 M NaOH, and filter through a 0.22 μm filter membrane to obtain a chlorogenic acid solution. Under nitrogen atmosphere and in the dark, add the chlorogenic acid solution to the dextran-modified protein dispersion at 120 rpm, and stir continuously at room temperature for 4 h. After the stirring reaction is complete, dialyze with deionized water at 4 °C for 48 h to remove free chlorogenic acid, and freeze-dry to obtain dextran-modified protein containing chlorogenic acid.

[0027] 6. Dissolve 2g of alanine-modified pectin in 150mL of a tert-butanol / water mixed solvent (tert-butanol to water volume ratio of 9:1), stir until completely dissolved, add 0.4g of dextran-modified protein-encapsulated chlorogenic acid, then add 5g of 3Å molecular sieve, maintaining the water activity of the system at 0.3, and add 0.12g of Novozym. Under a nitrogen atmosphere and in the dark, the mixture was stirred at 45°C and 200 rpm for 6 h. After the reaction was complete, the mixture was filtered through a 100-mesh sieve to remove lipase. The filtrate was slowly added to three volumes of anhydrous ethanol at 4°C and allowed to stand at 4°C for 2 h to precipitate the product. The precipitate was then centrifuged at 3000 rpm for 15 min. The precipitate was washed twice each with 70 wt% ethanol and anhydrous ethanol, and then dialyzed with deionized water for 24 h through a dialysis bag with a 50 kDa cutoff. After dialysis, the dialysate was freeze-dried at -80°C for 24 h to obtain an alanine-modified pectin-dextran-modified protein-chlorogenic acid ternary complex.

[0028] 7. By weight, take 50 parts of galactomannan, 20 parts of alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex and 3 parts of lutein. Put the above materials into a V-type mixer and mix at 20 rpm for 30 min to make the components fully uniform. Pass the mixed powder through an 80-mesh sieve to obtain a soluble dietary fiber composition.

[0029] Example 2: A method for preparing a soluble dietary fiber composition, comprising the following steps: 1. Under a nitrogen atmosphere, dissolve 3g of papain in 180mL of 0.05mol / L phosphate buffer (pH 7.0), stir at 200rpm for 30min in an ice bath at 3℃, add 35mL of 0.4mol / L L-cysteine ​​hydrochloride solution and 90mg of ethylenediaminetetraacetic acid, and continue stirring for 10min to obtain papain solution.

[0030] 2. Dissolve 1.4g of alanine in 100mL of 0.2mol / L phosphate buffer (pH 7.0) to obtain an alanine solution; mix the alanine solution with 50mL of papain solution to obtain a mixed solution; dissolve 7g of citrus pectin (D-galacturonic acid content ≥74%, degree of esterification 62~75%) in 150mL of 0.2mol / L phosphate buffer (pH 7.0) to obtain a pectin solution; add the pectin solution to the mixed solution while stirring at 400rpm, add 100mL of anhydrous ethanol, continue to purge with nitrogen for 15min to remove air, and then seal and stir at -15℃ and 400rpm for 18h.

[0031] 3. After the reaction was completed, 800 mL of anhydrous ethanol was added for precipitation. The mixture was then centrifuged at 4000 rpm for 5 min, and the precipitate was collected. The precipitate was then resuspended in 100 mL of 15 wt% trichloroacetic acid solution for 15 min. After suspension, the mixture was centrifuged at 8000 rpm for 10 min, and the supernatant was discarded. The precipitate was dialyzed through a dialysis bag with a molecular weight cutoff of 30 kDa and dialyzed in deionized water at 4 °C. After freeze-drying at -50 °C and 0.1 mbar, alanine-modified pectin was obtained.

[0032] 4. Dissolve 3g of whey protein isolate in 100mL of deionized water, adjust the pH to 8.0 with 0.1mol / L NaOH, stir at 300rpm for 30min at room temperature until completely dissolved, add 2.4g of oat β-glucan (average molecular weight 40kDa), stir to dissolve for 10min, and react at 300W and 70℃ for 60min, maintaining continuous stirring at 200rpm during the reaction. After the reaction is completed, quickly cool the reaction solution to 4℃ in an ice bath to terminate the reaction. Dialyze through a dialysis bag with a molecular weight cutoff of 50kDa for 36h, collect the retentate, freeze-dry it, and obtain the glucan-grafted modified protein.

[0033] 5. Dissolve 2.0 g of dextran-modified protein in 100 mL of distilled water, stir at 500 rpm until evenly dispersed, and adjust the pH to 9.0 with 0.1 mol / L NaOH to obtain a dextran-modified protein dispersion. Under a nitrogen atmosphere and in the dark, dissolve 0.5 g of chlorogenic acid in 100 mL of distilled water, adjust the pH to 9.0 with 0.1 M NaOH, and filter through a 0.22 μm filter membrane to obtain a chlorogenic acid solution. Under a nitrogen atmosphere and in the dark, add the chlorogenic acid solution to the dextran-modified protein dispersion at 120 rpm, and stir continuously at room temperature for 5 h. After the reaction is complete, dialyze through deionized water at 4 °C for 48 h to remove free chlorogenic acid, and freeze-dry to obtain dextran-modified protein containing chlorogenic acid.

[0034] 6. Dissolve 3g of alanine-modified pectin in 225mL of a tert-butanol / water mixed solvent (tert-butanol to water volume ratio of 9:1), stir until completely dissolved, add 0.9g of dextran-modified protein-encapsulated chlorogenic acid, then add 7g of 3Å molecular sieve, maintaining the water activity of the system at 0.4, and add 0.28g of Novozym. Under a nitrogen atmosphere and in the dark, the mixture was stirred at 48°C and 200 rpm for 6–8 h. After the reaction was complete, the mixture was filtered through a 100-mesh sieve to remove lipase. The filtrate was then slowly added to three volumes of anhydrous ethanol at 4°C and allowed to stand at 4°C for 2 h to precipitate the product. The precipitate was then centrifuged at 3000 rpm for 15 min. The precipitate was washed twice each with 70 wt% ethanol and anhydrous ethanol, and then dialyzed with deionized water for 30 h using a dialysis bag with a 50 kDa cutoff. After dialysis, the dialysate was freeze-dried at -80°C for 36 h to obtain an alanine-modified pectin-dextran-modified protein-chlorogenic acid ternary complex.

[0035] 7. By weight, take 60 parts of galactomannan, 30 parts of alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex, and 5 parts of lutein. Put the above materials into a V-type mixer and mix at 20 rpm for 30 minutes to ensure that the components are fully homogeneous. Pass the mixed powder through an 80-mesh sieve to obtain a soluble dietary fiber composition.

[0036] Example 3: A method for preparing a soluble dietary fiber composition, comprising the following steps: 1. Under a nitrogen atmosphere, dissolve 4g of papain in 180mL of 0.05mol / L phosphate buffer (pH 7.0), stir at 200rpm for 30min in an ice bath at 5℃, add 45mL of 0.4mol / L L-cysteine ​​hydrochloride solution and 160mg of ethylenediaminetetraacetic acid, and continue stirring for 10min to obtain papain solution.

[0037] 2. Dissolve 1.6g of alanine in 100mL of 0.2mol / L phosphate buffer (pH 7.0) to obtain an alanine solution; mix the alanine solution with 50mL of papain solution to obtain a mixed solution; dissolve 8g of citrus pectin (D-galacturonic acid content ≥74%, degree of esterification 62~75%) in 150mL of 0.2mol / L phosphate buffer (pH 7.0) to obtain a pectin solution; add the pectin solution to the mixed solution while stirring at 400rpm, add 100mL of anhydrous ethanol, continue to purge with nitrogen for 15min to remove air, and then seal and stir at -15℃ and 400rpm for 24h.

[0038] 3. After the reaction was completed, 800 mL of anhydrous ethanol was added for precipitation. The mixture was then centrifuged at 4000 rpm for 5 min, and the precipitate was collected. The precipitate was then resuspended in 100 mL of 15 wt% trichloroacetic acid solution for 15 min. After suspension, the mixture was centrifuged at 8000 rpm for 10 min, and the supernatant was discarded. The precipitate was dialyzed through a dialysis bag with a molecular weight cutoff of 30 kDa and dialyzed in deionized water at 4 °C. After freeze-drying at -50 °C and 0.1 mbar, alanine-modified pectin was obtained.

[0039] 4. Dissolve 4g of whey protein isolate in 100mL of deionized water, adjust the pH to 8.0 with 0.1mol / L NaOH, stir at 300rpm for 30min at room temperature until completely dissolved, add 3.4g of oat β-glucan (average molecular weight 40kDa), stir to dissolve for 10min, and react at 300W and 70℃ for 60min, maintaining continuous stirring at 200rpm during the reaction. After the reaction is completed, quickly cool the reaction solution to 4℃ in an ice bath to terminate the reaction. Dialyze through a dialysis bag with a molecular weight cutoff of 50kDa for 48h, collect the retentate, freeze-dry it, and obtain the glucan-grafted modified protein.

[0040] 5. Dissolve 4.0 g of dextran-modified protein in 200 mL of distilled water, stir at 500 rpm until evenly dispersed, and adjust the pH to 9.0 with 0.1 mol / L NaOH to obtain a dextran-modified protein dispersion. Under a nitrogen atmosphere and in the dark, dissolve 1 g of chlorogenic acid in 200 mL of distilled water, adjust the pH to 9.0 with 0.1 M NaOH, and filter through a 0.22 μm filter membrane to obtain a chlorogenic acid solution. Under a nitrogen atmosphere and in the dark, add the chlorogenic acid solution to the dextran-modified protein dispersion at 120 rpm, and stir continuously at room temperature for 6 h. After the stirring reaction is complete, dialyze against deionized water at 4 °C for 48 h to remove free chlorogenic acid, and freeze-dry to obtain dextran-modified protein containing chlorogenic acid.

[0041] 6. Dissolve 4g of alanine-modified pectin in 300mL of a tert-butanol / water mixed solvent (tert-butanol to water volume ratio of 9:1), stir until completely dissolved, add 1.6g of dextran-modified protein-encapsulated chlorogenic acid, then add 8g of 3Å molecular sieve, maintaining the water activity of the system at 0.5, and add 0.56g of Novozym. Under a nitrogen atmosphere and in the dark, the mixture was stirred at 50°C and 200 rpm for 8 h. After the reaction was complete, the mixture was filtered through a 100-mesh sieve to remove lipase. The filtrate was slowly added to three volumes of anhydrous ethanol at 4°C and allowed to stand at 4°C for 2 h to precipitate the product. The precipitate was then centrifuged at 3000 rpm for 15 min. The precipitate was washed twice each with 70 wt% ethanol and anhydrous ethanol. The precipitate was then dialyzed with deionized water for 36 h through a dialysis bag with a 50 kDa cutoff. After dialysis, the dialysate was freeze-dried at -80°C for 48 h to obtain an alanine-modified pectin-dextran-modified protein-chlorogenic acid ternary complex.

[0042] 7. By weight, take 70 parts of galactomannan, 40 parts of alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex, and 6 parts of lutein. Put the above materials into a V-type mixer and mix at 20 rpm for 30 minutes to ensure that the components are fully homogeneous. Pass the mixed powder through an 80-mesh sieve to obtain a soluble dietary fiber composition.

[0043] Comparative Example 1: A method for preparing a soluble dietary fiber composition, which differs from Example 1 in that the alanine-modified pectin in Example 1 is replaced with an equal amount of unmodified citrus high-ester pectin (esterification degree 62~75%), while the remaining steps are the same as in Example 1.

[0044] Comparative Example 2: A method for preparing a soluble dietary fiber composition, which differs from Example 1 in that the dextran-grafted modified protein in Example 1 is replaced with an equal amount of unmodified whey protein isolate, while the remaining steps are the same as in Example 1.

[0045] Comparative Example 3: A method for preparing a soluble dietary fiber composition, which differs from Example 1 in that alanine-modified pectin, dextran-grafted modified protein, chlorogenic acid, galactomannan, and lutein are directly physically mixed in the same weight proportions as in Example 1.

[0046] I. In vitro simulated digestion and chlorogenic acid release experiment (1) Simulated gastric digestion: The soluble dietary fiber compositions obtained in each example and comparative example were added to 0.1 M HCl solution (containing 3.2 mg / mL pepsin, pH 1.2), and shaken at 100 rpm for 2 h in a constant temperature water bath at 37℃ to obtain digestive juice; the digestive juice was centrifuged at 12000 rpm for 10 min at 4℃, and the supernatant was filtered through a 0.45 μm filter membrane. The chlorogenic acid content was detected by HPLC, and the gastric release rate was calculated by the ratio of the chlorogenic acid content in the soluble dietary fiber composition. Chromatographic conditions: C18 reversed-phase column (250×4.6 mm, 5 μm), mobile phase: acetonitrile:0.1% phosphoric acid water = 20:80 (v / v), flow rate 1.0 mL / min, detection wavelength 325 nm.

[0047] (2) Simulated small intestinal digestion: The pH of the digestive fluid obtained after gastric digestion was adjusted to 6.8 with 0.1 M NaOH, and 10 mg / mL trypsin and 12 mg / mL porcine bile extract were added. Digestion was continued at 37℃ and 100 rpm for 4 h. After centrifugation, the chlorogenic acid content was detected by HPLC, and the small intestinal release rate was calculated by the ratio of the chlorogenic acid content in the soluble dietary fiber composition.

[0048] (3) Colonic microbiota fermentation: After digestion in the small intestine, the digestive juice was transferred to GAM medium (pH 6.5) containing 10% human fecal suspension and anaerobic fermented at 37°C for 24 h. Samples were taken at 0, 2, 4, 6, 8, 12 and 24 h, and centrifuged at 12000 rpm for 10 min at 4°C. The supernatant was filtered through a 0.45 μm filter membrane and the chlorogenic acid content was determined by HPLC. The cumulative release rate in the colon was calculated by the ratio of the chlorogenic acid content in the soluble dietary fiber composition.

[0049] The test results are shown in Table 1: Table 1 Results of in vitro simulated digestion and chlorogenic acid release assay

[0050] As shown in Table 1, the soluble dietary fiber compositions obtained in Examples 1-3 achieved efficient colonic delivery and sustained release of chlorogenic acid, maintaining the integrity of the composition in the acidic environment of the stomach and effectively protecting chlorogenic acid from degradation. Comparative Example 1, lacking amide bonds, experienced rapid degradation of ester bonds, resulting in a large release within 0-4 hours. Comparative Example 3, with all components physically mixed and lacking a covalent network, exhibited extremely low colonic delivery efficiency, with most of the chlorogenic acid being lost in the stomach and small intestine.

[0051] II. Constipation and Stool Improvement Test Eighty male ICR mice (weighing 19-22g) were acclimatized for 7 days and then randomly divided into 8 groups of 10 mice each: blank control group, model control group, Example 1 group, Example 2 group, Example 3 group, Comparative Example 1 group, Comparative Example 2 group, and Comparative Example 3 group.

[0052] The example group and the comparative group were each administered the corresponding soluble dietary fiber composition (dissolved in physiological saline) by gavage at a rate of 1.2 g / kg BW for 7 days.

[0053] The blank control group and the model control group were administered equal volumes of physiological saline by gavage for 7 days, during which time the mice drank water and ate normally.

[0054] Seven days after gavage, the mice were separated into individual cages and kept in a 20-hour fast but allowed free access to water. Five pellets were collected from the mouse feces, weighed, resuspended in pre-cooled PBS, homogenized in an ice bath, centrifuged at 12000g for 10 minutes at 4°C, and the supernatant was collected. The pH was adjusted to 3.0 with hydrochloric acid, extracted with ether, and the content of short-chain fatty acids (SCFA) in the feces was detected by gas chromatography-mass spectrometry. The results are shown in Table 2.

[0055] After a 20-hour fast with no restriction on water, the model control group, the example group, and the comparative group were administered compound diphenoxylate via gavage (20 mg / kg BW), while the blank control group received an equal volume of physiological saline. One hour later, the blank control group and the model control group were administered ink via gavage, while the example group and the comparative group were administered the corresponding soluble dietary fiber composition containing ink via gavage. Normal water and food intake were then maintained, and the time of the first black stool (min) for each mouse, the number of black stool particles and their weight (g) within 10 hours were observed and recorded. The results are shown in Table 3.

[0056] Table 2. Results of detection of short-chain fatty acid (SCFA) content in mouse feces

[0057] The contents of acetic acid, propionic acid, and butyric acid in the feces of mice in Examples 1-3 were significantly increased compared with those in Comparative Examples 1-3. Comparative Example 1 used natural pectin, which itself does not produce butyric acid; butyric acid comes entirely from galactomannan. Lacking the protective effect of alanine-modified pectin, the galactomannan in Comparative Example 1 was rapidly fermented, limiting butyric acid production. Comparative Example 2 did not use dextran-modified protein; the natural protein denatured in the tert-butanol / water system, resulting in low covalent cross-linking efficiency and an incomplete ternary network, leading to ineffective protection of both galactomannan and pectin, thus affecting the short-chain fatty acid content. Comparative Example 3 physically mixed all components without any cross-linking; galactomannan and pectin were partially degraded or rapidly passed through the stomach and small intestine, reducing the substrate reaching the colon, resulting in the lowest short-chain fatty acid content.

[0058] Table 3. Time of first black stool in mice, number and weight of black stool particles within 10 hours.

[0059] As shown in Table 3, compared with the results of the blank control group and the model control group, there were significant differences in the time to first black stool (min), the number of black stool particles and the total weight of black stool (g) within 10 hours, indicating that the constipation model was successfully established.

[0060] In Examples 1-3, the time to first black stool in mice was significantly faster than in Control Groups 1-3. After galactomannan entered the mice's bodies, it rapidly absorbed water to form a lubricating gel, accelerating fecal excretion. The ternary complex effectively protected some of the galactomannan, allowing it to continue its function in the colon. The number of fecal particles excreted after 10 hours was also significantly higher than in the Control Groups. The slow decomposition of the ternary polymer, releasing short-chain amino acids, stimulated intestinal peristalsis, increasing defecation frequency and fecal volume.

[0061] Although the natural pectin in Comparative Example 1 still has the ability to absorb water and swell, it lacks an amide bond network, which weakens its protective effect on galactomannan. Furthermore, natural pectin cannot achieve a sustained-release effect, resulting in insufficient stimulation of intestinal peristalsis in the later stages and a reduction in the number of stool particles. Comparative Example 2 did not use modified protein, which reduced the cross-linking efficiency of the ternary polymer and resulted in insufficient protection of galactomannan, thus delaying the first black stool. Comparative Example 3 only used physical mixing of the components, and the galactomannan was not protected. It absorbed water or was diluted in the stomach and small intestine, and its laxative effect was greatly weakened when it reached the colon, thus resulting in the latest time for the first black stool.

[0062] In summary, the soluble dietary fiber composition obtained by this invention has good application prospects in the preparation of functional foods or drugs for weight loss, fat reduction, prevention or relief of constipation.

[0063] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A soluble dietary fiber composition, characterized in that, By weight, it consists of 50-70 parts of galactomannan, 20-40 parts of alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex and 3-6 parts of lutein; The preparation method of the alanine-modified pectin-dextran-modified protein-chlorogenic acid ternary complex is as follows: S11. Dissolve alanine-modified pectin in a tert-butanol / water mixed solvent at a solid-liquid ratio of 1g:75mL. Stir until completely dissolved, then add dextran-modified protein-encapsulated chlorogenic acid, add 3Å molecular sieve, maintain the water activity of the system at 0.3~0.5, add lipase Novozym 435, and stir the reaction at 45~50℃ and 200rpm for 6~8h under a nitrogen atmosphere, in the dark. S12. After the reaction is complete, the solution is filtered through a 100-mesh sieve. The filtrate is slowly added to an excess of anhydrous ethanol at 4°C and allowed to stand at 4°C for 2 hours. After centrifugation and washing, the precipitate is dialyzed through a dialysis bag with a cutoff of 50 kDa for 24-36 hours. The dialysate is then freeze-dried to obtain an alanine-modified pectin-dextran-modified protein-chlorogenic acid ternary complex. The preparation method of the alanine-modified pectin is as follows: S21. Mix alanine solution and papain solution at a volume ratio of 2~2.5:1 to obtain a mixed solution; add pectin solution to the mixed solution at a volume ratio of 1~1.2:1 at 400 rpm, then add anhydrous ethanol, purge air with nitrogen, and then seal and stir at -15℃ and 400 rpm for 12~24 h. S22. After the reaction is complete, add excess anhydrous ethanol to precipitate the product. Centrifuge and collect the precipitate. Resuspend the precipitate in 15wt% trichloroacetic acid solution and stir for 15 min. Centrifuge again and discard the supernatant. Dialyze the product in deionized water at 4℃ using a dialysis bag with a molecular weight cutoff of 30 kDa. After freeze-drying, alanine-modified pectin is obtained. The preparation method of the dextran-modified protein is as follows: Whey protein isolate was dissolved in deionized water, the pH was adjusted to 8.0, and the mixture was stirred at room temperature until completely dissolved. Dextran was then added and stirred for 10 minutes. The mixture was then ultrasonically stirred at 300W and 70℃ for 60-80 minutes. After the reaction was completed, the mixture was quickly placed in an ice bath to stop the reaction. After dialyzing through a 50kDa molecular weight cutoff dialysis bag, the retentate was collected and freeze-dried to obtain dextran-modified protein.

2. The soluble dietary fiber composition according to claim 1, characterized in that, The mass ratio of alanine-modified pectin to dextran-modified protein containing chlorogenic acid is 1:0.2~0.4; the amount of lipase Novozym 435 added is 5~10% of the total mass of alanine-modified pectin and dextran-modified protein containing chlorogenic acid.

3. The soluble dietary fiber composition according to claim 1, characterized in that, The method for preparing the papain solution is as follows: Under a nitrogen atmosphere, papain is dissolved in 0.05M phosphate buffer at pH 7.0 at a solid-liquid ratio of 1g:90mL. The solution is stirred for 30min in an ice bath at 0-5℃. Then, 0.4M L-cysteine ​​hydrochloride solution and ethylenediaminetetraacetic acid are added, and the mixture is stirred for another 10min to obtain the papain solution. The mass ratio of L-cysteine ​​hydrochloride to papain is 0.7-1.0:

1. The amount of ethylenediaminetetraacetic acid added is 2-4% of the mass of papain.

4. The soluble dietary fiber composition according to claim 1, characterized in that, The method for preparing the dextran-modified protein containing chlorogenic acid is as follows: S1. Dissolve dextran-modified protein in 50 mL of distilled water at a solid-liquid ratio of 1 g: 50 mL, stir well, and adjust the pH to 8.0-9.0 to obtain a dextran-modified protein dispersion; Under a nitrogen atmosphere and in the dark, dissolve chlorogenic acid in distilled water at a solid-liquid ratio of 1 g: 200 mL, adjust the pH to 9.0, and filter through a 0.22 μm filter membrane to obtain a chlorogenic acid solution; Under a nitrogen atmosphere and in the dark, chlorogenic acid solution was added to the dextran-modified protein dispersion at a volume ratio of 1:1 and stirred continuously at room temperature for 4-6 hours. After the reaction was completed, the mixture was dialyzed and freeze-dried to obtain dextran-modified protein containing chlorogenic acid.

5. The soluble dietary fiber composition according to claim 1, characterized in that, The mass ratio of whey protein isolate to dextran is 1:0.75~0.

85.

6. A method for preparing the soluble dietary fiber composition according to any one of claims 1 to 5, characterized in that, Includes the following steps: Take galactomannan, alanine-modified pectin-glucan-modified protein-chlorogenic acid ternary complex and lutein in proportion, mix well, and pass through an 80-mesh sieve to obtain a soluble dietary fiber composition.

7. The use of the soluble dietary fiber composition according to any one of claims 1 to 5 in the preparation of functional foods or medicines for the prevention or relief of constipation.

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