Method for preparing leguminous seed coat dietary fiber and application thereof

Abstract

The application provides a preparation method of legume seed coat dietary fiber and application thereof. The application provides a preparation method of legume seed coat dietary fiber, which comprises the following steps: crushing legume seed coat to obtain legume seed coat powder; performing first extraction treatment on the legume seed coat powder by using alkali liquor, and collecting a first extract; performing bleaching treatment on the first extract, and collecting a second extract; performing second extraction treatment on the second extract by using an acid eutectic solvent, and collecting a third extract; and performing micro-jet high-pressure homogenization treatment on the third extract to obtain the legume seed coat dietary fiber. The preparation method can be used for preparing legume seed coat dietary fiber from soybean hulls, chickpea hulls and other legume seed coats, and can improve the dispersibility, suspensibility and uniformity of the legume seed coat dietary fiber. The food prepared from the legume seed coat dietary fiber can improve the food quality from different aspects, and the legume seed coat dietary fiber is a natural dietary fiber source, and can increase the nutritional value of the food.

Description

Technical Field

[0001] This invention relates to the food field, and more specifically, to a method for preparing dietary fiber from legume seed coats and its applications. Background Technology

[0002] Legume seed coats, such as soybean and chickpea husks, are byproducts of legume seed processing and are traditionally used as low-value feed additives or discarded. However, in the food and food additive sector, the increasing market demand for low-energy and low-fat foods makes the use of fat substitutes an effective strategy. These seed coats are rich in nutrients; in particular, the dietary fiber in the seed coat can serve as a fat substitute, reducing the calorie content of foods while maintaining desirable taste and texture. Nevertheless, existing technologies have limitations, such as the insolubility of certain seed coat components and the inadequacy of traditional fat substitutes in mimicking the sensory properties of fat. Therefore, the extraction and application of dietary fiber from soybean husks still require further research. Summary of the Invention

[0003] This invention aims to at least partially address one of the technical problems existing in the prior art. To this end, this invention provides a method for preparing soybean hull dietary fiber, soybean hull dietary fiber, and food products. This invention improves the dispersibility, suspension, and uniformity of soybean hull dietary fiber and chickpea hull dietary fiber through modification treatment. Soybean husk dietary fiber was used as a fat substitute in the preparation of ice cream. The ice cream with added soybean husk dietary fiber had a sensory evaluation close to that of full-fat ice cream, improving the acceptance and market competitiveness of low-fat ice cream. It also increased the viscosity and stability of the ice cream emulsion, extended the melting time, slowed the melting rate, and improved the texture and shelf life of the ice cream. Furthermore, the inventors used soybean husk dietary fiber to prepare fruit juice and milk, increasing their stability; used it as a whitening agent to prepare milk gummies and jellies, improving their color; and used it as a thickener in yogurt, resulting in less whey separation, a smoother surface, better coagulation, and a more delicate and richer texture. The inventors further discovered that adding soybean husk dietary fiber to food helps with weight regulation and reduction, has a positive impact on lipid metabolism and cardiovascular disease-related risk factors, helps maintain gut health, and provides benefits for the development of nutritional and functional foods.

[0004] In one aspect of the present invention, a method for preparing dietary fiber from soybean skin is provided. According to an embodiment of the present invention, the method includes: pulverizing soybean skin to obtain soybean skin powder; performing a first extraction treatment on the soybean skin powder using an alkaline solution to collect a first extract; bleaching the first extract to collect a second extract; performing a second extraction treatment on the second extract using an acidic eutectic solvent to collect a third extract; and subjecting the third extract to microfluidic high-pressure homogenization to obtain the dietary fiber from soybean skin.

[0005] According to the method for preparing soybean hull cellulose of the present invention, soybean hulls are first pulverized to produce soybean hull powder, thereby increasing the surface area and facilitating subsequent extraction. Next, the soybean hull powder undergoes a first extraction using an alkaline solution to dissolve and release dietary fiber. The first extract is then bleached using a bleaching agent such as hydrogen peroxide to remove lignin and pigments, improving the purity and whiteness of the dietary fiber. Then, a second extract is subjected to a second extraction using an acidic eutectic solvent to further purify the dietary fiber and remove remaining lignin and non-cellulose components. Finally, a third extract undergoes microfluidic high-pressure homogenization, where high-speed shear force refines and disperses the dietary fiber, improving its uniformity and stability, thereby obtaining high-quality soybean hull dietary fiber, providing better dispersibility and functionality for subsequent applications such as food additives.

[0006] According to an embodiment of the present invention, the bean husk includes soybean husk, chickpea husk, and other legume seed coats.

[0007] According to an embodiment of the present invention, the method further includes: passing the pulverized particles through a 40-80 mesh sieve to obtain the soybean hull powder.

[0008] According to an embodiment of the present invention, the concentration of the alkaline solution is 3 w / v% to 8 w / v%.

[0009] According to an embodiment of the present invention, the temperature of the first extraction process is 60-90°C, the time is 4-8 hours, and the rotation speed is 300-700 rpm.

[0010] According to an embodiment of the present invention, the method further includes: first washing the first extract with water until the pH of the filtrate is 6-8, then washing the first extract with ethanol and drying it.

[0011] According to an embodiment of the present invention, the method further includes: first washing the second extract with water and then drying it.

[0012] According to an embodiment of the present invention, the bleaching treatment includes: heating and stirring the first filter residue with a hydrogen peroxide solution; the heating and stirring temperature is 80-100°C.

[0013] According to an embodiment of the present invention, the heating and stirring time is 2 to 6 hours.

[0014] According to an embodiment of the present invention, the rotation speed of the heating and stirring is 300 to 700 rpm.

[0015] According to an embodiment of the present invention, the acidic eutectic solvent includes lactic acid and choline chloride.

[0016] According to an embodiment of the present invention, the molar ratio of lactic acid to choline chloride is (8:1) to (10:1).

[0017] According to an embodiment of the present invention, the temperature of the second extraction process is 80–100°C.

[0018] According to an embodiment of the present invention, the second extraction process takes 2 to 6 hours.

[0019] According to an embodiment of the present invention, the rotation speed of the second extraction process is 300 to 700 rpm.

[0020] According to an embodiment of the present invention, the pressure of the microjet high-pressure homogenization treatment is 100MPa to 200MPa.

[0021] According to an embodiment of the present invention, the pore size of the microjet high-pressure homogenization treatment is 100-200 μm.

[0022] According to an embodiment of the present invention, the microjet high-pressure homogenization treatment is performed 2 to 4 times.

[0023] In another aspect of the invention, a soybean skin dietary fiber is provided. According to an embodiment of the invention, the soybean skin dietary fiber is obtained by any of the methods described above for preparing soybean skin dietary fiber.

[0024] Those skilled in the art will understand that the features and advantages described above for the method of preparing soybean skin dietary fiber also apply to this soybean skin dietary fiber, and will not be repeated here.

[0025] In another aspect, the present invention provides a food product. According to an embodiment of the invention, it includes the aforementioned soybean hull dietary fiber. Through extensive experimentation, the inventors unexpectedly discovered that adding soybean hull dietary fiber to food can improve its quality in various ways. According to an embodiment of the invention, ice cream was prepared using soybean hull dietary fiber as a fat substitute. The ice cream with added soybean hull dietary fiber had a sensory evaluation close to that of full-fat ice cream, improving the acceptance and market competitiveness of low-fat ice cream, increasing the viscosity and stability of the ice cream emulsion, extending the melting time of the ice cream, slowing down the melting rate, and improving the texture and shelf life of the ice cream. Furthermore, the inventors also used soybean hull dietary fiber to prepare fruit juice and milk, increasing their stability; used soybean hull dietary fiber as a whitening agent to prepare milk gummies and jellies, improving their color; and used soybean hull dietary fiber as a thickener to prepare yogurt, resulting in less whey separation, a smoother surface, better coagulation, and a more delicate and richer taste. According to an embodiment of the invention, ice cream with added soybean hull dietary fiber helps with weight regulation and reduction, has a positive impact on lipid metabolism and cardiovascular disease-related risk factors, and helps maintain gut health.

[0026] According to an embodiment of the present invention, the dietary fiber content of the bean curd skin is 0.25% to 5%, preferably 0.5% to 2.5%.

[0027] In another aspect, the present invention proposes the use of the aforementioned soybean peel dietary fiber in food preparation. According to embodiments of the present invention, the soybean peel dietary fiber can be added to food as a fat substitute, stabilizer, whitening agent, thickener, etc., to improve the quality of the food in various ways. According to embodiments of the present invention, the food can be a functional food, health product, pharmaceutical, etc.

[0028] Those skilled in the art will understand that the features and advantages described above for the method of preparing dietary fiber from soybean skin are also applicable to this use, and will not be repeated here.

[0029] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0031] Figure 1 This is a schematic diagram of the soybean hull dietary fiber extraction process in Example 1 of the present invention;

[0032] Figure 2This is a microscopic examination result of the product obtained during the extraction of dietary fiber from soybean hulls in Example 1 of the present invention.

[0033] Figure 3 This is a TEM image showing the results of the alkaline extraction of soybean hulls product in Example 1 of the present invention.

[0034] Figure 4 This is a TEM image showing the results of the study on dietary fiber in soybean hulls in Example 1 of this invention.

[0035] Figure 5 This is a SEM image of the alkali-extracted soybean hull product from Example 1 of the present invention.

[0036] Figure 6 This is a SEM image showing the results of the investigation of dietary fiber in soybean hulls in Example 1 of the present invention;

[0037] Figure 7 This is a graph showing the composition of dietary fiber in soybean hulls in Example 1 of the present invention.

[0038] Figure 8 This is a graph showing the results of the investigation of the water-holding capacity, oil-holding capacity, and water absorption and swelling characteristics of soybean hull dietary fiber in Example 1 of the present invention;

[0039] Figure 9 The image shows the infrared spectrum of soybean hull dietary fiber in Example 1 of this invention.

[0040] Figure 10 This is a graph showing the color change of the ice cream emulsion in Example 2 of the present invention;

[0041] Figure 11 This is a diagram showing the fluorescence microscopy results of the ice cream emulsion in Example 2 of the present invention;

[0042] Figure 12 This is a graph showing the results of the viscosity test of the ice cream emulsion in Example 2 of the present invention;

[0043] Figure 13 This is a graph showing the results of the investigation into the shear thinning behavior of ice cream emulsion in Example 2 of the present invention;

[0044] Figure 14 This is a graph showing the amplitude scanning results of the ice cream emulsion in Example 2 of the present invention;

[0045] Figure 15 This is a graph showing the amplitude scanning results of the ice cream emulsion in Example 2 of the present invention;

[0046] Figure 16 This is a graph showing the results of the small-amplitude oscillation shearing test of ice cream emulsion in Example 2 of the present invention;

[0047] Figure 17 This is a graph showing the results of the small-amplitude oscillation shearing test of ice cream emulsion in Example 2 of the present invention;

[0048] Figure 18 This is a diagram showing the macroscopic melting results of the ice cream emulsion in Example 2 of the present invention;

[0049] Figure 19 This is a graph showing the results of the aeration of the ice cream emulsion in Example 2 of the present invention;

[0050] Figure 20 This is a graph showing the results of the investigation on the melting amount of ice cream emulsion in Example 2 of the present invention;

[0051] Figure 21 This is a graph showing the results of the ice cream emulsion melting rate investigation in Example 2 of the present invention;

[0052] Figure 22 This is a graph showing the DSC results of the ice cream emulsion in Example 2 of the present invention;

[0053] Figure 23 This is a sensory evaluation diagram of the ice cream emulsion in Embodiment 2 of the present invention;

[0054] Figure 24 This is a graph showing the results of the stability study of soybean hull dietary fiber in Example 3 of the present invention;

[0055] Figure 25 This is a graph showing the results of the static stability test of reconstituted soybean hull dietary fiber in Example 3 of the present invention;

[0056] Figure 26 The image shows the results of the stability test of the juice in Example 3 of the present invention. The left image shows the juice without added soybean skin dietary fiber, and the right image shows the juice with added soybean skin dietary fiber.

[0057] Figure 27 The image shows the results of the milk stability test in Example 3 of the present invention. The left image shows milk without added soybean skin dietary fiber, and the right image shows milk with added soybean skin dietary fiber.

[0058] Figure 28 The images show the finished milk gummies from Embodiment 3 of the present invention. The left image shows milk gummies with added soybean skin dietary fiber, and the right image shows milk gummies without added soybean skin dietary fiber.

[0059] Figure 29 The image shows the finished jelly product in Embodiment 3 of the present invention. The left image shows the jelly with added soybean skin dietary fiber, and the right image shows the jelly without added soybean skin dietary fiber.

[0060] Figure 30 The image shows the finished yogurt product in Embodiment 3 of the present invention. The left image shows yogurt with added soybean skin dietary fiber, and the right image shows yogurt without added soybean skin dietary fiber.

[0061] Figure 31This is a schematic diagram of the chickpea skin dietary fiber extraction process in Example 4 of the present invention;

[0062] Figure 32 This is a microscopic examination result of the product extracted from chickpea skin dietary fiber in Example 4 of the present invention.

[0063] Figure 33 This is a TEM image showing the results of the alkaline-extracted chickpea skin product in Example 4 of this invention.

[0064] Figure 34 This is a TEM image showing the results of the dietary fiber examination of chickpea skin in Example 4 of the present invention;

[0065] Figure 35 This is a graph showing the dietary fiber composition analysis of chickpea skin in Example 4 of the present invention;

[0066] Figure 36 Figure 5 shows the results of the study on the effects of feeding different groups of ice cream mixtures on mice in Example 5 of this invention; (A) is a schematic diagram of the experimental design; (B) is a graph showing the results of the weight of mice in each group; (C) is a graph showing the results of the dry weight of feces of mice in each group within 24 hours; (D) is a graph showing the water content of feces of mice in each group after 21 days of feeding ice cream; (E) is a graph showing the liquid content of feces of mice in each group; (F) is a graph showing the total cholesterol content of feces of mice in each group; (G) is a graph showing the AChE content in the blood of mice in each group after 21 days of feeding ice cream; (H) is a graph showing the results of feeding different groups of mice with ice cream. (I) Blood TBA content after 21 days of ice cream feeding; (J) Blood TC content after 21 days of ice cream feeding; (K) Blood HDL content after 21 days of ice cream feeding; (L) Blood LDL content after 21 days of ice cream feeding; (M) Graph showing the results of atherosclerosis index assessment in mice of each group; (N) Graph showing the results of H&E assessment in major organs (heart, liver, spleen, lung, kidney) of mice of each group.

[0067] Figure 37 The results of the daily food intake survey of mice in each group are shown in the figure;

[0068] Figure 38 Figures show the results of the investigation of the gut microbiota of mice in each group; (A) shows the results of the investigation of the Chao1 diversity index of mice in each group; (B) shows the results of the investigation of the Shannon diversity index of mice in each group; (C) shows the results of the investigation of the Faith's PD diversity index of mice in each group; (D) shows the principal coordinate analysis of the gut microbiota of mice in each group; (E) shows the relative abundance of the phylum-level gut microbiota of mice in each group; and (F) shows the relative abundance of the genus-level gut microbiota of mice in each group. Detailed Implementation

[0069] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0070] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0071] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0072] In this document, the terms “comprising” or “including” are open-ended expressions, meaning that they include the contents specified in this invention, but do not exclude other aspects.

[0073] In this document, the terms “optionally,” “optionally,” or “optionally” generally refer to an event or condition that may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0074] In this paper, the term "DSC" stands for Differential Scanning Calorimetry. DSC obtains the thermal properties of materials, such as phase transition temperature, enthalpy change, and specific heat capacity, by measuring the heat flow changes related to temperature changes.

[0075] In this paper, the term "G′" refers to the storage modulus, an important parameter in rheology, which is a measure of a material's ability to store energy under periodic stress.

[0076] In this paper, the term "G" refers to the loss modulus, an important parameter in rheology, which is a measure of a material's ability to dissipate energy under periodic stress.

[0077] In this paper, the term "DES" refers to acidic eutectic solvent, which is a mixture formed by mixing hydrogen bond acceptors and hydrogen bond donors in a certain proportion, and whose freezing point is significantly lower than the melting point of each component when it exists alone.

[0078] In this paper, the term "TEM" stands for transmission electron microscopy, a high-resolution microscopy technique that uses an electron beam to penetrate an ultrathin sample to obtain images of the internal structure of the material.

[0079] In this paper, the term "SEM" refers to scanning electron microscopy, which is a microscopy technique that uses an electron beam to scan the surface of a sample and obtains information about the surface morphology and structure of the sample by detecting the signal generated by the interaction between the sample and the electron beam.

[0080] In this article, the term "SHCF" is synonymous with "soybean hull hemicellulose" and "soybean hull dietary fiber".

[0081] This invention proposes a method for preparing dietary fiber from soybean skin, soybean skin dietary fiber, and ice cream, which will be described in detail below.

[0082] Methods for preparing dietary fiber from soybean skin

[0083] In one aspect of the present invention, a method for preparing dietary fiber from soybean skin is provided. According to an embodiment of the present invention, the method includes: pulverizing soybean skin to obtain soybean skin powder; performing a first extraction treatment on the soybean skin powder using an alkaline solution, collecting a first extract; bleaching the first extract, collecting a second extract; performing a second extraction treatment on the second extract using an acidic eutectic solvent, collecting a third extract; and subjecting the third extract to microfluidic high-pressure homogenization to obtain the dietary fiber from soybean skin. This improves the dispersibility, suspension, and uniformity of the dietary fiber from soybean skin.

[0084] According to an embodiment of the present invention, the bean husk includes soybean husk, chickpea husk, and other legume seed coats.

[0085] For example, the bean husks include, but are not limited to, soybean husks, chickpea husks, black bean husks, red bean husks, mung bean husks, lentil husks, cowpea husks, pea husks, broad bean husks, and lentil husks.

[0086] According to an embodiment of the present invention, the process further includes: passing the pulverized particles through a 40-80 mesh sieve to obtain the soybean hull powder. This ensures particle size consistency, removes impurities, and improves subsequent extraction efficiency.

[0087] According to embodiments of the present invention, the concentration of the alkali solution is 3 w / v% to 8 w / v, for example, it can be 3 w / v%, 4 w / v%, 5 w / v%, 6 w / v%, 7 w / v%, or 8 w / v. This removes lignin and improves extraction efficiency.

[0088] According to an embodiment of the present invention, the temperature of the first extraction process is 60–90°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, or 90°C; the time is 4–8 hours, for example, 4 hours, 5 hours, 6 hours, 7 hours, or 8 hours; and the rotation speed is 300–700 rpm, for example, 300 rpm, 400 rpm, 500 rpm, 600 rpm, or 700 rpm. This ensures a complete reaction, improving extraction efficiency and yield.

[0089] According to an embodiment of the present invention, the first filter residue is first washed with water until the pH of the filtrate is 6-8, specifically, the pH of the filtrate can be adjusted to 7. Then, the first filter residue is washed with ethanol and dried. Thus, washing with water neutralizes the pH and removes impurities, while washing with ethanol more effectively removes residual alkali and other less polar impurities. The filter residue dries more easily, accelerating the entire extraction process and thus helping to improve the dispersibility, suspension, and uniformity of the dietary fiber in soybean skin.

[0090] According to an embodiment of the present invention, the bleaching treatment includes: heating and stirring the first filter residue with a hydrogen peroxide solution; the heating and stirring temperature is 80-100°C, for example, 80°C, 85°C, 90°C, 95°C, or 100°C. This removes excess lignin, as well as pigments and impurities, thereby improving the dispersibility, suspension, and uniformity of the dietary fiber in the soybean skin.

[0091] According to an embodiment of the present invention, the heating and stirring time is 2 to 6 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours. This ensures a complete reaction, improving extraction efficiency and yield.

[0092] According to an embodiment of the present invention, the heating and stirring speed is 300-700 rpm, for example, 300 rpm, 400 rpm, 500 rpm, 600 rpm, or 700 rpm. This ensures a complete reaction, improving extraction efficiency and yield.

[0093] According to embodiments of the present invention, the acidic eutectic solvent includes lactic acid and choline chloride. Thus, lactic acid and choline chloride, as acidic eutectic solvents, can effectively extract and improve the physical properties of dietary fiber, such as dispersibility, suspension, and uniformity, enhance its water-holding and oil-holding properties, and improve extraction efficiency. Simultaneously, both lactic acid and choline chloride are food-grade substances, ensuring the safety of the final product.

[0094] According to embodiments of the present invention, the molar ratio of lactic acid to choline chloride is (8:1) to (10:1), for example, 8:1, 9:1, or 10:1. This further improves extraction efficiency and yield.

[0095] According to an embodiment of the present invention, the temperature of the second extraction process is 80–100°C. This ensures a sufficient reaction, improving extraction efficiency and yield.

[0096] According to an embodiment of the present invention, the second extraction process takes 2 to 6 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours. This allows for a sufficient reaction, improving extraction efficiency and yield.

[0097] According to an embodiment of the present invention, the rotation speed of the second extraction process is 300-700 rpm, for example, 300 rpm, 400 rpm, 500 rpm, 600 rpm, or 700 rpm. This ensures a sufficient reaction, improving extraction efficiency and yield.

[0098] According to an embodiment of the present invention, the pressure of the microjet high-pressure homogenization treatment is 100MPa to 200MPa, for example, 100MPa, 150MPa, or 200MPa. This improves the dispersibility, suspension, and uniformity of the dietary fiber in soybean skin.

[0099] According to an embodiment of the present invention, the pore size of the microfluidic high-pressure homogenization treatment is 100–200 μm, for example, 100 μm, 150 μm, or 200 μm. This improves the dispersibility, suspension, and uniformity of the dietary fiber in soybean skin.

[0100] According to an embodiment of the present invention, the microfluidic high-pressure homogenization treatment is performed 2 to 4 times, for example, 2, 3, or 4 times. This further improves the dispersibility, suspension, and uniformity of the dietary fiber in soybean skin.

[0101] Soybean curd skin dietary fiber

[0102] In another aspect of the invention, a soybean hull dietary fiber is provided. According to an embodiment of the invention, the soybean hull fiber is obtained by the method described in any of the preceding claims for preparing soybean hull dietary fiber. As a result, the obtained soybean hull dietary fiber exhibits good dispersibility, suspension, and uniformity, and its water-holding capacity, oil-holding capacity, and water absorption and swelling properties are all improved.

[0103] Those skilled in the art will understand that the features and advantages described above for the method of preparing soybean skin dietary fiber also apply to this soybean skin dietary fiber, and will not be repeated here.

[0104] food

[0105] In another aspect of the invention, a food product is proposed, comprising, according to an embodiment of the invention, the aforementioned soybean skin dietary fiber. Thus, the addition of soybean skin dietary fiber can improve the structure of the food, providing a better taste or appearance. Ice cream prepared using soybean skin dietary fiber as a fat substitute has a sensory evaluation close to that of full-fat ice cream, increasing the acceptance and market competitiveness of low-fat ice cream, improving the viscosity and stability of the ice cream emulsion, extending the melting time of the ice cream, slowing down the melting rate, and improving the texture and shelf life of the ice cream. Furthermore, the inventors have also used soybean skin dietary fiber to prepare fruit juice and milk, increasing stability; used soybean skin dietary fiber as a whitening agent to prepare milk gummies and jellies, improving color; and used soybean skin dietary fiber as a thickener to prepare yogurt, resulting in less whey separation, a smoother surface, better coagulation, and a more delicate and richer taste. According to an embodiment of the invention, ice cream with added soybean skin dietary fiber helps with weight regulation and reduction, has a positive impact on lipid metabolism and cardiovascular disease-related risk factors, and helps maintain gut health. According to embodiments of the present invention, the dietary fiber from soybean skin prepared using the present invention can be added to food as a fat substitute, stabilizer, whitening agent, and thickener to improve food performance.

[0106] Those skilled in the art will understand that the features and advantages described above for the method of preparing dietary fiber from soybean skin are also applicable to other foods that require improvement in these properties, and will not be repeated here.

[0107] According to an embodiment of the present invention, the dietary fiber content of the soybean skin in the food is 0.25% to 5%, preferably 0.5% to 2.5%, for example, it can be 0.5%, 1.0%, 1.5%, 2.0%, or 2.5%. This further improves the performance of the food.

[0108] use

[0109] In another aspect, the present invention proposes the use of the aforementioned soybean peel dietary fiber in food preparation. According to embodiments of the present invention, the soybean peel dietary fiber can be added to food as a fat substitute, stabilizer, whitening agent, thickener, etc., to improve the quality of the food in various ways. According to embodiments of the present invention, the food can be a functional food, health product, pharmaceutical, etc. According to specific embodiments of the present invention, the food includes ice cream, fruit juice, milk, gummies, jelly, and yogurt.

[0110] Those skilled in the art will understand that the features and advantages described above for the method of preparing dietary fiber from soybean skin are also applicable to this use, and will not be repeated here.

[0111] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0112] Example 1

[0113] In this embodiment, reference Figure 1 Dietary fiber from soybean hulls was extracted using the following method:

[0114] 1. Weigh a certain amount of soybean hull raw material and grind it into powder using a grinder. Pass the powder through a 60-mesh sieve. Weigh 2% (w / v) of soybean hull powder and heat it to 80°C in a 5% (w / v) alkaline solution. Stir at 500 rpm for 6 hours. Filter the residue and wash it with distilled water until the pH reaches 7. Add ethanol and dry the residue to obtain the first extract. Treat the 2% (w / v) first extract with 4% hydrogen peroxide solution at 90°C and 500 rpm for 4 hours to remove the lignin. Wash the residue repeatedly with distilled water and collect the residue. Dry the residue to obtain the second extract.

[0115] 2. The second extract obtained above was treated using the acidic eutectic solvent method (DES). Specifically, the acidic eutectic solvent (DES solution) used was lactic acid and choline chloride in a molar ratio of 9:1. 2% (w / v) of the second extract was weighed and added to 40 mL of DES solution. The mixture was stirred at 90°C and 500 rpm for 4 h. The residue was collected by suction filtration, dried, and the third extract was obtained.

[0116] 3. Weigh 1% (w / v) of the third extract after the previous step and dissolve it in water. Then, process it three times using a microfluidic high-pressure homogenizer with a 200μm pore size and 150MPa to obtain uniformly dispersed and stable soybean skin dietary fiber. After drying or freeze-drying, grind it into powder for long-term storage.

[0117] Soybean husk dietary fiber was observed using optical microscopy, TEM, and SEM, respectively. The results are as follows: Figure 2 As shown, optical microscopy revealed that the alkali-extracted cellulose was in a blocky and rod-shaped aggregated state. After bleaching, most of the lignin was removed, and the structure between the dietary fibers opened up, becoming dispersed short rods. DES treatment further removed lignin, and the rod-shaped structure of the dietary fiber became loose. After microfluidic high-pressure homogenization, the dietary fiber was transformed into SHCF with a network and filamentous structure. Figure 3 The image shown is a TEM image of the product obtained from crude extraction of soybean hulls. The cellulose extracted by alkali is in block form. Figure 4The image shown is a TEM image of SHCF, the final product of soybean hull dietary fiber after microfluidic high-pressure homogenization. After microfluidic high-pressure homogenization, the dietary fiber exhibits a network and filamentous structure; the particle size is reduced to below 100 nm, and the specific surface area is increased. Figure 5 The image shown is a SEM image of the product obtained from crude extraction of soybean hulls. The cellulose extracted by alkali is in a blocky and rod-shaped polymer state. Figure 6 The image shown is a SEM image of SHCF, the final product of soybean hull dietary fiber homogenized by microfluidic high-pressure homogenization. After microfluidic high-pressure homogenization, the dietary fiber exhibits a network and filamentous structure; the particle size is reduced to below 100 nm, and the specific surface area increases. Figures 2-6 As shown, the extracted soybean hull dietary fiber changes from block and rod shape to network and filament shape, thus significantly improving its dispersibility in water and enhancing its stability, providing a foundation for its subsequent application in food.

[0118] Component analysis and property characterization of dietary fiber in soybean hulls, including monosaccharide components such as... Figure 7 As shown in Table 1, the results indicate that the dietary fiber composition of soybean hulls prepared by this method meets health and safety standards, with hemicellulose as the main component. The water-holding capacity, oil-holding capacity, and water absorption and swelling properties of soybean hull dietary fiber were investigated, and the results are shown in Table 1. Figure 8 As shown, the soybean hull dietary fiber prepared by this method exhibits varying degrees of improvement in water-holding capacity, oil-holding capacity, and water absorption and swelling properties. Infrared spectroscopy was performed on the products after alkali extraction, bleaching, and DES treatment, and the results are as follows. Figure 9 As shown in the figure. The results in summary indicate that, compared with crudely extracted soybean hull dietary fiber, the treated soybean hull dietary fiber exhibits significantly improved water-holding capacity, oil-holding capacity, and water absorption and swelling properties.

[0119] Table 1. Dietary fiber composition of soybean hulls

[0120]

[0121] Example 2

[0122] As shown in Table 2, ice cream emulsions containing different concentrations of soybean hull dietary fiber were prepared by mixing ingredients according to the proportions listed in the table. The emulsions were heated to 60℃ and stirred until dissolved, then sheared at 10,000 rpm for 20 minutes using a shear mill. After aging at 4℃ for 12 hours, the aged emulsions were added to an ice cream machine and churned and aerated at a low temperature to obtain ice cream. The color changes of each group of ice cream emulsions are shown in the table below. Figure 10 As shown in the figure. The ice cream emulsions of each group were observed under a fluorescence microscope, and the results are as follows. Figure 11 As shown, green fluorescent whey protein is uniformly dispersed on the surface of oil droplets, while soybean skin dietary fiber is dispersed in the aqueous phase.

[0123] The inventors investigated the rheological properties of low-fat and full-fat ice cream emulsions made from soybean hull dietary fiber. Rheological properties reflect the flow behavior and texture of ice cream. All samples exhibited shear-thinning behavior. Higher shear-thinning behavior in the mixtures indicates the stability of the system properties under lower shear rate processing conditions, allows for easier pumping of the mixture, and provides the desired texture and mouthfeel of the final product. Results are as follows... Figure 12 As shown, the viscosity of low-fat ice cream emulsion with added soybean hull dietary fiber increased significantly, and the viscosity also increased with increasing cellulose content. This increase in viscosity can also be explained by the water-binding capacity of cellulose. The immiscible polysaccharides and proteins separate into two phases, leading to an increase in the concentration of each phase, which makes self-association between polysaccharides or proteins more favorable. Due to the presence of the extended network of cellulose material, and due to water retention and molecular confinement, the results are as follows... Figure 13 As shown, the addition of dietary fiber significantly increased the viscosity, consistency index, and shear thinning behavior of the mixture.

[0124] Table 2. Soybean husk dietary fiber low-fat ice cream recipe

[0125]

[0126] Because of R 2 >0.9, the results are shown in Table 3. The consistency coefficient (k) gradually increases with the increase of dietary fiber concentration in soybean skin, and the flow index (n) is between 0 and 1, which are all pseudoplastic fluids.

[0127] Table 3. Rheological parameters of ice cream

[0128]

[0129] Note: There are significant differences in the values ​​of different letters in the same column (P<0.05).

[0130] The inventors conducted amplitude scanning studies on each group of ice cream emulsions, and the results are as follows: Figure 14 , Figure 15As shown, the amplitude scanning results show that G″ is significantly higher than G′ in all groups, confirming the dominant role of viscous properties in these emulsions. The rheological properties of the emulsion are mainly determined by the dispersed phase structure. G′ and G″ in the low-fat group are significantly lower than those in the full-fat and cellulose-added groups, and both G′ and G″ increase with increasing SHCF concentration. Under strains of 0.01–100, G′ and G″ in the full-fat and low-fat groups remain unchanged, indicating no structure formation. However, in the SHCF-added low-fat group, G′ and G″ decrease when a certain strain is applied, indicating a structural transformation from viscous to elasticity-dominant, demonstrating that structure formation occurs after SHCF addition. Therefore, structural collapse occurs under greater stress, and the higher the SHCF concentration, the lower the stress required for structural collapse. Small amplitude oscillatory shear (SAOS) measurements were performed to understand the relationship between microstructure and viscoelasticity of the ice cream mixture. The results are as follows: Figure 16 , Figure 17 As shown, G″ is higher than G′ for all samples, indicating that viscosity dominates. All samples show that G′ increases with increasing frequency, suggesting that viscoelastic properties depend on frequency and that the network structure may consist of non-covalent crosslinks (e.g., hydrophobic interactions and hydrogen bonds). The fact that different viscoelastic behaviors were observed at each concentration suggests that the addition of cellulose affects the viscoelasticity of the ice cream mixture.

[0131] The inventors further examined the melting process of each group of ice creams, and the macroscopic melting conditions of each group of ice creams are as follows: Figure 18 As shown. The air volume of each group of ice creams is as follows. Figure 19 As shown in the figure, the results of the quantitative statistical analysis of the melting amount of ice cream in each group are as follows: Figure 20 As shown in the figure, the results indicate that ice cream with added soybean skin dietary fiber melted less over the same time period, and the higher the amount added, the lower the melting rate. The results of quantitative statistical analysis of the melting rates of each group of ice cream are as follows: Figure 21 As shown in the figure, the results indicate that ice cream with added soybean skin dietary fiber melts at a lower rate, and the higher the amount added, the lower the melting rate. DSC analysis was performed on each group of ice creams, and the results are as follows. Figure 22 As shown in Table 4, the inventors also investigated the enthalpy, freezing temperature, and ice crystal content of each group of ice creams. The results indicate that the addition of dietary fiber from soybean skin can prolong the melting time of ice cream, slow down the melting rate, and reduce the ice crystal content.

[0132] Table 4. Physical parameters of ice cream

[0133]

[0134] Twenty healthy sensory evaluators with no known taste or smell disorders were selected, with a male-to-female ratio of 1:1, and aged between 22 and 30 years. Prior to the sensory assessment, evaluators received training and were informed of the purpose of the experiment. Overall liking was rated using a 9-point happierism scale, and the average was calculated. Participants were asked to provide a core evaluation of the attributes selected in Table 5 on a 9-point scale, from "lowest intensity" (=1) to "highest intensity" (=9). The results are shown in Table 6, and the statistical analysis results are as follows: Figure 23 As shown, adding soybean skin dietary fiber to ice cream does not affect overall likability.

[0135] Table 5. Sensory Evaluation Attributes

[0136]

[0137]

[0138] Table 6. Sensory Evaluation Scores

[0139] sample Full fat low-fat 1% SHCF - Low Fat 2% SHCF - Low Fat Appearance <![CDATA[6.9±1.1 a ]]> <![CDATA[5.2±2.1 a ]]> <![CDATA[6.5±1.5 a ]]> <![CDATA[6.3±1.6 a ]]> Color <![CDATA[7.3±1.4 a ]]> <![CDATA[5.3±1.9 a ]]> <![CDATA[6.2±1.4 ab ]]> <![CDATA[6.5±1.3 ab ]]> Texture <![CDATA[6.6±1.5 a ]]> <![CDATA[5.4±2.3 a ]]> <![CDATA[6.2±1.4 a ]]> <![CDATA[6.1±1.5 a ]]> Creamy <![CDATA[6.8±1.2 a ]]> <![CDATA[4.2±1.7 b ]]> <![CDATA[5.3±1.1 b ]]> <![CDATA[5.4±1.4 b ]]> cold feeling <![CDATA[6.2±1.0 ab ]]> <![CDATA[6.9±0.9 a ]]> <![CDATA[5.3±0.8 bc ]]> <![CDATA[4.9±1.9 c ]]> grainy texture <![CDATA[2.6±0.8 b ]]> <![CDATA[4.3±1.3 a ]]> <![CDATA[3.9±1.6 ab ]]> <![CDATA[3.9±1.7 ab ]]> Melting time in mouth <![CDATA[5.4±1.1 b ]]> <![CDATA[4.5±1.7 aa ]]> <![CDATA[6.3±0.9 a ]]> <![CDATA[6.5±1.8 a ]]> dense feeling <![CDATA[6.7±1.3 a ]]> <![CDATA[5.6±1.5 a ]]> <![CDATA[6.3±1.3 a ]]> <![CDATA[6.2±0.6 a ]]> Smoothness <![CDATA[6.4±1.5 a ]]> <![CDATA[4.7±1.3 b ]]> <![CDATA[6.0±0.8 a ]]> <![CDATA[6.2±1.0 a ]]> Softness <![CDATA[6.3±1.3 a ]]> <![CDATA[4.8±1.2 b ]]> <![CDATA[6.5±0.8 a ]]> <![CDATA[6.3±0.8 a ]]> viscous feeling <![CDATA[6.1±1.0 a ]]> <![CDATA[4.0±1.2 b ]]> <![CDATA[5.8±0.9 a ]]> <![CDATA[6.3±1.2 a ]]> bean flavor <![CDATA[1.1±0.3 b ]]> <![CDATA[1.2±0.4 b ]]> <![CDATA[1.5±0.7 ab ]]> <![CDATA[1.9±1.0 a ]]> Overall likability <![CDATA[7.2±0.9 a ]]> <![CDATA[4.4±1.1 b ]]> <![CDATA[6.5±0.8 a ]]> <![CDATA[6.9±1.2 a ]]>

[0140] Note: The numerical differences between different letters in the same row are significant (P<0.05).

[0141] Example 3

[0142] To expand the application of soybean skin dietary fiber in the food industry, the inventors conducted numerous experiments and unexpectedly discovered that adding soybean skin dietary fiber to food can improve the quality of food in various ways. Therefore, they investigated the addition of soybean skin cellulose to different foods.

[0143] 1. Stability of dietary fiber in soybean skin

[0144] Soybean hull dietary fiber (1%) was dissolved in water and allowed to stand. After autoclaving, the solution was obtained as follows: Figure 24 As shown, the results indicated that soybean hull dietary fiber showed no significant changes in water within 0–45 days. Reconstituted freeze-dried and dried soybean hull dietary fiber by ultrasonic cell disruptor at 10 kHz for 1 min or conventional ultrasound for 30–40 min, followed by autoclaving, yielded the following results: Figure 25 As shown in the results, the dietary fiber in soybean hulls under different drying treatments showed no significant changes within 0–15 days. These results indicate that the dietary fiber in soybean hulls has good stability and remains stable even after autoclaving.

[0145] Adding 2% soybean hull dietary fiber to fruit juice and letting it stand, then comparing it with fruit juice without added soybean hull dietary fiber, the results are as follows: Figure 26As shown in the figure, the left side of the juice is juice without added soybean skin dietary fiber, and the right side is juice with added soybean skin dietary fiber. The juice with added soybean skin dietary fiber showed no significant changes within 0 to 60 days and can be stored stably.

[0146] Adding 1.5% soybean hull dietary fiber to milk and letting it stand, and comparing it with milk without added soybean hull dietary fiber, the results are as follows: Figure 27 As shown in the figure, the left side of the image shows milk without added soybean skin dietary fiber, while the right side shows milk with added soybean skin dietary fiber. The milk with added soybean skin dietary fiber showed no significant changes within 0 to 60 days and can be stored stably.

[0147] 2. The soybean skin dietary fiber of this application is used as a whitening agent and added to common foods that require whitening agents, such as milk gummies and jelly. Soybean skin dietary fiber is added during the production process and compared with products without added whitening agents.

[0148] Milk Soft Candy Preparation Method: 1. Mix 60g starch, 25g white sugar, 0.12g citric acid, and 80ml water until smooth. Heat over low heat to 60℃. 2. Pour 170ml boiling water into milk and cook until the milk becomes a syrup. Stir rapidly until smooth. Add the syrup from step 1 to the milk syrup in three batches: first add 20ml and stir well; then add 40ml; finally, add all the remaining syrup and cook until thickened. During this process, cook in two groups (one group with 1% soybean cellulose, the other without). 3. Cook the syrup while stirring constantly for about one hour, until the temperature reaches approximately 115-120℃. 4. Cool, spread a layer of starch or grease a griddle with vegetable oil to prevent sticking, and cut into pieces. Result as shown. Figure 28 As shown in the image, the left side of the picture shows milk gummies with added soybean skin dietary fiber, while the right side shows milk gummies without added soybean skin dietary fiber. The results show that the milk gummies with added soybean skin dietary fiber are whiter, while the milk gummies without added soybean skin dietary fiber are yellowish, indicating that soybean skin dietary fiber can be added to food as a whitening agent.

[0149] Jelly Preparation Method: 1. Add 15g of gelatin powder to 50ml of room temperature water, stir well, and let stand for about 15 minutes to allow the gelatin powder to fully absorb water and swell. 2. In another container, boil 70g of white sugar and 130ml of water (one group adds 1% soybean hull cellulose, the other does not) until the sugar is completely dissolved. 3. Mix the gelatin and sugar water well. 4. Filter the mixture and pour it into molds. 5. Refrigerate at 4℃ until set. The result is as follows. Figure 29 As shown in the figure, the left side of the image shows jelly with added soybean skin dietary fiber, while the right side shows jelly without added soybean skin dietary fiber. The results show that the jelly with added soybean skin dietary fiber is milky white, while the jelly without added soybean skin dietary fiber is transparent, further illustrating that soybean skin dietary fiber can be added to food as a whitening agent.

[0150] 3. The soybean skin dietary fiber of this application was used as a thickener and added to yogurt during the production process, and compared with yogurt without added thickener.

[0151] Commercially available pure milk and commercially available yogurt starter were mixed according to the instructions. One group was supplemented with 1% soybean hull dietary fiber, while the other group was not. The mixtures were fermented at 40°C, cooled, and observed. The results are as follows: Figure 30 As shown, the left image is yogurt with added soybean skin dietary fiber, and the right image is yogurt without added soybean skin dietary fiber. The results show that the yogurt with added soybean skin dietary fiber has less whey separation, a smoother surface, better coagulation effect, and a more delicate and mellow taste.

[0152] Example 4

[0153] In this embodiment, the method of Embodiment 1 is followed, except that soybean hulls are replaced with chickpea hulls. The flowchart is as follows. Figure 31 As shown, chickpea skin dietary fiber was obtained. The chickpea dietary fiber was observed using an optical microscope and TEM, respectively. Figure 32 The image shown is an optical microscope image of the product during the extraction of chickpea skin dietary fiber. The cellulose extracted by alkali is in a blocky polymer state. After bleaching, most of the lignin is removed, and the structure between the dietary fibers opens up, becoming dispersed rods. DES treatment further removes lignin, and the rod-shaped structure of the dietary fiber becomes loose. After microfluidic high-pressure homogenization, the dietary fiber is transformed into chickpea skin dietary fiber with a network and filamentous structure. Figure 33 The image shown is a TEM image of the product obtained from crude extraction of chickpea skins. The alkali-extracted cellulose is in block form. Figure 34 The image shown is a TEM image of the final product after microfluidic high-pressure homogenization of chickpea husk dietary fiber. After microfluidic high-pressure homogenization, the dietary fiber exhibits a network and filamentous structure. The particle size is reduced to below 100 nm, and the specific surface area increases, which significantly enhances the dispersibility and stability of chickpea husk dietary fiber in aqueous solution. Figures 32-34 As shown, the results indicate that the dietary fiber obtained from chickpea husks is similar to that from soybean husks obtained in Example 1, proving that the method of this application is applicable to the seed coats of various legumes. The inventors further conducted component analysis on the chickpea husks, and the results are shown in Table 7 and... Figure 35 As shown, the chickpea skin components prepared by this method meet health and safety standards.

[0154] Table 7. Dietary fiber composition of chickpea skin

[0155]

[0156] Example 5

[0157] In this embodiment, the inventors further conducted in vivo studies to evaluate the health benefits of the dietary fiber prepared according to the present invention.

[0158] 1. Male C57BL / 6N mice (6-8 weeks old) were purchased from Beijing Xibeifu Biotechnology Co., Ltd. The rearing environment was 22-24℃, 60% humidity, and a 12-hour light-dark cycle. All animal experiments were conducted in accordance with the "Guidelines for the Husbandry and Use of Laboratory Animals" and approved by the Beijing Laboratory Animal Ethics Committee (Aw92804202-4-2). Mice were randomly divided into four groups of eight each. Each group was administered 200 μL of ice cream mixture twice daily by gavage, while the control group received distilled water instead. The experimental procedure is as follows: Figure 36 As shown in Figure A, all mice consumed a normal diet during the experiment. Weight changes and food intake were recorded daily. Fresh fecal samples were collected at days 0, 1, 2, 7, 14, and 21 and stored at -80°C until further analysis.

[0159] On day 21, mice in each group were administered ice cream mixture by gavage for 30 minutes, followed by 1% ink. The laxative effect of SHCF was assessed using small intestinal propulsion speed, the time to the appearance of the first blue feces, and the amount of feces excreted within 6 hours. On day 23, mice in each group were administered ice cream mixture by gavage for 30 minutes, followed by ink for 40 minutes. They were then immediately euthanized by decapitation, and the intestinal lumen was opened and the mesentery separated. The intestine was gently stretched into a straight line, and the length of the small intestine from the pylorus to the tip of the ink container was measured. The formula for calculating the ink propulsion rate is as follows:

[0160] Ink propulsion rate (%) = (Ink propulsion length (cm)) / (Total small intestine length (cm)) × 100

[0161] Finally, the mice were euthanized, and their blood, liver, bile, heart, spleen, lungs, kidneys, colon contents, and cecal contents were collected for a series of histochemical analyses.

[0162] 2. During the 21-day experiment, the effects of oral administration of SHCF-rich ice cream on mouse body weight and fecal excretion were evaluated. The results are as follows: Figure 36 As shown in B-36C, mice fed full-fat ice cream showed a significant increase in body weight (***P<0.001), suggesting that low-fat ice cream may help control body weight. Notably, mice fed SHCF low-fat ice cream had a significantly lower rate of weight gain compared to mice fed non-SHCF low-fat ice cream (*P<0.05). Furthermore, the SHCF group also showed a significantly lower rate of weight gain compared to the control group provided only with drinking water (*P<0.05). Figure 36The daily fecal excretion results in group C showed that the SHCF low-fat group had a significantly increased fecal volume compared to other groups (**P<0.01, ***P<0.001). The increased fecal volume and the observed trend in weight change suggest that the reduced weight gain in the SHCF low-fat group may be due to SHCF promoting increased fecal volume. Consistent with these findings, insoluble dietary fiber, such as hemicellulose, is involved in absorption and excretion processes, including increasing fecal volume and stimulating intestinal motility.

[0163] On day 21 after feeding each group ice cream, the laxative effect of SHCF was assessed by the time of the first black stool, the amount of stool in 6 hours, and the intestinal propulsion rate. The results are shown in Table 8. The results showed that the time to first excretion of black feces in the SHCF low-fat group (89.17±11.11 vs 122.00±16.31, 125.83±18.28, 127.17±12.99 min) was significantly shorter than that in the other three groups (P<0.05). The 6-hour fecal volume (19.83±4.54 pellets) and fecal mass (140±17.89 mg) were also significantly higher than those in the other three groups (P<0.05). The intestinal propulsion rate (83.59±6.46 vs 65.97±2.17, 67.68±2.81, 65.45±8.22%) was also significantly higher in the SHCF low-fat group than in the other three groups. Fecal water content results for each group after 22 days of feeding are shown in the table below. Figure 36 D. The water content of feces in the SHCF low-fat group mice was significantly higher than that in the blank group, low-fat group, and full-fat group (P<0.05), at 62.24%, 50.67%, 49.39%, and 49.14%, respectively. Lipids in the feces were extracted using CM solution (chloroform:methanol = 2:1), and the total lipid content of feces in each group was obtained, as shown below. Figure 36 As shown in Figure E, the total fat content in the feces of mice in the SHCF low-fat group (231.091 vs 98.60, 114.65, 113.73) was significantly higher than that in the other three groups (P<0.05). The total cholesterol (TC) content in the feces of mice in the SHCF low-fat group was also higher than that in the other three groups. Figure 36 F). Neurotransmitters play an important role in regulating gastrointestinal motility. Acetylcholinesterase (AChE) is an acetylcholinesterase that promotes smooth muscle contraction and intestinal peristalsis in the digestive tract. The AChE level was higher in the long-term SHCF intake group ( Figure 36 (G) This is consistent with the results regarding defecation time, stool volume, and intestinal propulsion rate, indicating that SHCF promotes intestinal peristalsis. These results suggest that feeding mice with SHCF-based low-fat ice cream can improve intestinal transport by increasing stool volume and intestinal motility, thereby increasing the excretion of fat and triglycerides in mouse feces, which is beneficial for maintaining body weight and preventing obesity.

[0164] Serum levels of total bile acids (TBA), total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) are shown in the figures below. Figure 36 H, 36I, 36J, 36K, 36L. The results showed that the TBA, TC, and TG levels in the SHCF low-fat group were significantly lower than those in the low-fat ice cream group (*P<0.05, **P<0.01), and closer to the control group. SHCF has a small particle size and increased specific surface area, which facilitates the absorption of bile from dietary fiber in the small intestine, while bile acids cannot be absorbed by the small intestinal wall and return to the liver. The liver absorbs cholesterol from the blood to replenish consumed bile acids to meet normal metabolic needs, thereby effectively regulating the levels of TG, HDL-C, TC, and LDL-C in mouse serum. The atherosclerosis index (AI) is an indicator for assessing the severity of atherosclerosis; the AI ​​of all experimental groups was measured. Figure 36 As shown in M, an AI value below the threshold of 4 indicates a lower degree of atherosclerosis and a reduced risk of cardiovascular and cerebrovascular diseases. Conversely, an AI value greater than or equal to 4 indicates the presence of atherosclerosis, with higher values ​​indicating more severe conditions and a higher risk of related diseases. Figure 36 M shows the AI ​​index for each group. The results showed that long-term consumption of full-fat ice cream significantly increased the probability of cardiovascular and cerebrovascular diseases (**P<0.01), while SHCF low-fat ice cream could slow down the increase of the AI ​​index and play a certain role in preventing the occurrence of cardiovascular and cerebrovascular diseases. Figure 36 N represents the H&E tissue sections of the heart, liver, spleen, lung, and kidney from mice in the control group and the SHCF low-fat group dissected on day 21. The results indicate that there were no significant differences in the major organs of mice fed SHCF low-fat ice cream compared to the control group, suggesting that SHCF can be used as a potential safe fat alternative to ice cream.

[0165] Table 8. Effects of each sample group on mouse defecation.

[0166]

[0167] The numerical values ​​for different letters in the same row showed significant differences (P<0.05).

[0168] The inventors further investigated the toxicological properties and biosafety of SHCF low-fat ice cream. The results are as follows: Figure 37 As shown, there was no significant difference in food intake among all mice during the feeding period (P>0.5), demonstrating that SHCF did not suppress appetite or affect food intake in mice. During the experiment, the mice exhibited lively behavior, glossy and smooth fur, and active feeding.

[0169] 3. Long-term consumption of high-fat foods may lead to gut microbiota imbalance, thus adversely affecting health. The SHCF involved in this invention, as a fat substitute in ice cream, exhibits potential prebiotic properties. It can be fermented by gut microbiota to produce short-chain fatty acids (SCFAs), thereby regulating gut microbiota structure and maintaining gut health. In α-diversity analysis, this invention uses the Chao1, Shannon, and Faith's PD indices to assess gut microbiota species richness, species distribution evenness, and evolution-based diversity. The results are as follows... Figure 38 As shown in A–C, an increase in the Chao1 index indicates an increase in the total number of species, an increase in the Shannon index indicates improved community diversity, and an increase in the Faith's PD index represents enhanced evolutionary diversity. Compared with the control group and other experimental groups, the Chao1, Shannon, and Faith's PD indices were significantly increased in the SHCF low-fat ice cream group, indicating that SHCF can significantly improve the species richness, evenness, and evolutionary diversity of the gut microbiota. β-diversity analysis, using principal coordinate analysis (PCoA), demonstrated the differences in gut microbiota composition among different treatment groups. The results are as follows: Figure 38 As shown in Figure D, the SHCF low-fat ice cream group was closer to the control group in the PCoA analysis, indicating that its main microbial composition was similar to the control group, while it differed significantly from other treatment groups. This suggests the effect of SHCF on gut microbiota composition. The inventors further evaluated the effects of different groups on the gut microbiota. At the phylum level, the results are as follows: Figure 38As shown in Figure E, the fecal microbiota of mice mainly includes Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, Microparasitic Glycolytics (TM7), Verrucous Microbes, Soft-walled Bacteria, Deferobacteria, Cyanobacteria, and Acidobacteria. Among them, Firmicutes and Bacteroidetes are the dominant phyla, accounting for more than 80% of the total bacteria. The study found that the relative abundance of Actinobacteria (2.48%, 2.57%, 1.76% vs 3.70%) and TM7 (1.32%, 1.44%, 0.22% vs 2.48%) in the feces of mice fed SHCF low-fat ice cream was significantly increased. In addition, the inventors further analyzed the effect of SHCF on the intestinal microbiota. The changes in Lactobacillus were the most obvious. The percentage of Lactobacillus in the intestines of mice fed full-fat ice cream decreased to 2.25%, while the percentage of Lactobacillus in the low-fat group decreased to 3.78%, indicating that fat intake affects the fixation of this genus. Conversely, compared to the healthy group, the number of lactic acid bacteria in mice fed the SHCF low-fat group was not reduced (9.38% vs 9.84%), indicating that SHCF helps avoid the loss of lactic acid bacteria caused by fat intake. Notably, the number of *Ischemicum faecalis* spp. in the SHCF low-fat group was significantly increased, being 2.33 times, 3.28 times, and 5.51 times higher than in the control group, low-fat group, and full-fat group, respectively. These results indicate that high fat intake significantly reduces the number of *Ischemicum faecalis*, while SHCF promotes its proliferation. The study report points out that *Ischemicum faecalis* is an active glucose metabolite that produces butyrate and lactate, which helps regulate host weight and prevent obesity. Furthermore, high fat intake reduces the number of *Desulfovibrio* and *Adlerococcus*, and the addition of SHCF as a fat substitute in low-fat ice cream alleviated this reduction to some extent. In summary, these results demonstrate that SHCF has a probiotic effect by regulating gut microbiota, promoting the growth of beneficial bacteria, and increasing the richness and evenness of the gut microbiota.

[0170] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0171] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing dietary fiber from soybean skin, characterized in that, include: The bean curd sheets are pulverized to obtain bean curd sheet powder; The bean curd powder was subjected to a first extraction treatment using an alkaline solution, and the first extract was collected. The first extract was bleached, and the second extract was collected. The second extract was subjected to a second extraction treatment using an acidic eutectic solvent, and the third extract was collected. The third extract was subjected to microfluidic high-pressure homogenization to obtain the soybean skin dietary fiber.

2. The method according to claim 1, characterized in that, The bean husks include the seed coats of legumes such as soybean husks and chickpea husks.

3. The method according to claim 1, characterized in that, Further includes: The pulverized particles are passed through a 40-80 mesh sieve to obtain the bean curd powder; Optionally, the concentration of the alkaline solution is 3 w / v% to 8 w / v%. Optionally, the temperature of the first extraction process is 60–90°C; Optionally, the first extraction process takes 4 to 8 hours; Optionally, the rotation speed of the first extraction process is 300 to 700 rpm.

4. The method according to claim 1, characterized in that, Further includes: The first extract was first washed with water until the pH of the filtrate was 6-8, then washed with ethanol and dried. Optionally, the second extract is first washed with water and then dried.

5. The method according to claim 1, characterized in that, The bleaching process includes: heating and stirring the first extract with a hydrogen peroxide solution; The heating and stirring temperature is 80–100°C; Optionally, the heating and stirring time is 2 to 6 hours; Optionally, the heating and stirring speed is 300 to 700 rpm.

6. The method according to claim 1, characterized in that, The acidic eutectic solvent includes lactic acid and choline chloride; Optionally, the molar ratio of lactic acid to choline chloride is (8:1) to (10:1); Optionally, the temperature of the second extraction process is 80–100°C; Optionally, the second extraction process takes 2 to 6 hours; Optionally, the rotation speed of the second extraction process is 300 to 700 rpm.

7. The method according to claim 6, characterized in that, The pressure of the microjet high-pressure homogenization process is 100MPa to 200MPa; Optionally, the pore size of the microjet high-pressure homogenization treatment is 100–200 μm; Optionally, the microjet high-pressure homogenization treatment is performed 2 to 4 times.

8. A type of dietary fiber from soybean skin, characterized in that, The dietary fiber from soybean skin is obtained by the method for preparing dietary fiber from soybean skin as described in any one of claims 1 to 7.

9. A food product, characterized in that, include: The dietary fiber from soybean skin as described in claim 8.

10. The food product according to claim 9, characterized in that, The dietary fiber content of the bean curd skin in the food is 0.25% to 5%, preferably 0.5% to 2.5%.

11. The use of the soybean skin dietary fiber according to claim 8 in the preparation of food.

Images