Vinasse dietary fiber with hypoglycemic activity and preparation method thereof

Abstract

The invention provides vinasse dietary fiber with hypoglycemic activity and a preparation method of the vinasse dietary fiber. The vinasse dietary fiber with relatively high purity is obtained by performing alkali soaking, sodium chlorite bleaching, crushing and drying on the vinasse. The prepared vinasse dietary fiber can effectively improve type 2 diabetes mellitus hyperglycemia, reduce fasting blood glucose level and improve sugar tolerance, and can be applied to preparation of functional food, health care products, medicines and feeds with the blood glucose reducing effect.

Description

Technical Field

[0001] The invention belongs to the field of functional foods, and particularly relates to distiller's grains dietary fiber with blood sugar-lowering activity and a preparation method thereof. Background Art

[0002] Liquor lees are a major byproduct of traditional solid-state liquor production. The main raw materials are sorghum, wheat, rice, and potatoes. They are rich in nutrients such as crude fiber, crude protein, and crude fat. my country's baijiu lees production is relatively large, so resource utilization is an inevitable trend in the development of the baijiu lees processing industry, which is experiencing strong growth. The Chinese Nutrition Society defines dietary fiber as: a polymer of carbohydrates with a degree of polymerization ≥3 that occurs naturally in plants, is extracted from plants, or is directly synthesized, is edible, cannot be digested and absorbed by the human small intestine, and is beneficial to human health. Dietary fiber is divided into two major categories: soluble dietary fiber (SDF) and insoluble dietary fiber (IDF). Soluble dietary fiber primarily consists of pectins and gums, which are found in naturally occurring non-fibrous substances. Insoluble dietary fiber refers to non-starch polysaccharides that are insoluble in hot water, such as cellulose, hemicellulose, and lignin, and are found in plant cell walls. Dietary fiber has the potential to lower blood lipids, blood pressure, and reduce fat accumulation, and is therefore attracting increasing research attention.

[0003] The high crude fiber content in distiller's grains primarily refers to proportional increases in cellulose, hemicellulose, and lignin, with crude fiber reaching 24.17% and crude ash reaching 15.42%. Research on methods for extracting dietary fiber from distiller's grains is currently attracting increasing attention. However, existing research focuses on the separation and extraction of substances, lacking understanding of how dietary fiber from distiller's grains can be incorporated into products, hindering the application of functional ingredients in distiller's grains. Zhang Shixian et al. attempted to extract water-soluble dietary fiber from Maotai sauce-flavor distiller's grains using alkaline and enzymatic methods. The resulting product was a caramel-colored powder, which was dark and unsuitable for use as a food ingredient, limiting its application. Hou Xuguang et al. collected flocs using calcium chloride treatment, then subjected them to acid decalcification, alkaline treatment, and hydrogen peroxide bleaching to produce a powdery distiller's grains dietary fiber product with a whitish to white color. This method offers advantages such as high fiber content, high water-holding capacity, and high swelling power. However, hydrogen peroxide is unstable and volatile, making it difficult to control the dosage during bleaching, making it unsuitable for large-scale production. Yu Guo invented a method for separating high-purity cellulose, hemicellulose, and lignin. The method uses enzymes to remove protein from distiller's grains. The grains are then treated with organic solvents at high temperature and high pressure for solid-liquid separation, yielding solid cellulose. The liquid component is then precipitated with water to yield lignin, and the remaining liquid is vacuum distilled to yield high-purity hemicellulose. The isolated product is highly pure and contains few reaction byproducts, but its biological activity has not been verified. Ji Jiaju's "Method for Extracting Dietary Fiber from Distiller's Grains" utilizes pulping, heat-insulated enzymatic hydrolysis, and ultrasonic extraction of soluble dietary fiber from distiller's grains. While the extraction efficiency is high, the equipment investment is high, hindering commercialization. Zhang Suyi et al. used extrusion pretreatment and ultrasonic-assisted enzymatic hydrolysis to treat distiller's grains, achieving a high yield of water-soluble dietary fiber from the grains and demonstrating good antioxidant activity. However, animal experiments were not conducted to verify the product's in vivo activity. Summary of the Invention

[0004] In response to the problems of complex procedures, high costs and lack of in vivo activity verification in the existing technology, the present invention obtains high-purity vinasse dietary fiber by alkaline soaking, sodium chlorite bleaching, crushing and drying the vinasse, and verifies its in vivo hypoglycemic activity using a type 2 diabetes mouse model, thereby obtaining dietary fiber with hypoglycemic activity.

[0005] The technical solutions provided by the present invention are as follows:

[0006] The first aspect of the present invention provides a method for preparing distiller's grains dietary fiber with hypoglycemic activity, characterized in that the preparation method comprises the steps of alkali soaking, bleaching, refining and drying and crushing.

[0007] Furthermore, the preparation method comprises the following steps:

[0008] (1) Alkali soaking: The lees were passed through a 20-mesh sieve to remove impurities and retain the rice husks. The rice husks were soaked in a 5% (w / v) NaOH solution for 48 hours, with the mass ratio of rice husks to NaOH solution being 1:5. After the soaking, the NaOH was removed by repeated washing with water, and the first precipitate was collected by filtration.

[0009] (2) Bleaching: Add 1-3% (w / v) NaClO2 solution to the first precipitate, with the mass ratio of the first precipitate to the NaClO2 solution being 1:5. After mixing, adjust the pH to 5 with 10% (v / v) acetic acid, heat to 70-80°C, stir and decolorize for 1-3 hours, and collect the second precipitate by filtration;

[0010] (3) Refining: Grind the second precipitate with water, with the volume ratio of the second precipitate to water being 1:1. Pass the slurry through a 100-mesh filter, squeeze and drain the water to obtain the third precipitate.

[0011] (4) Drying and pulverizing: drying the third precipitate at 60° C., pulverizing, drying, and sieving the dried material to 80-100 mesh, and obtaining a distiller's grains dietary fiber product.

[0012] Furthermore, in step (2), the stirring and decolorizing step is repeated 1 to 2 times until the precipitate becomes light yellow, and then washed with water multiple times to remove NaClO2.

[0013] Furthermore, the lees are white wine lees or yellow wine lees.

[0014] Furthermore, the vinasse dietary fiber has a powdery appearance and a light yellow to slightly white color.

[0015] The second aspect of the present invention provides a preparation method according to the first aspect for preparing distiller's grains dietary fiber.

[0016] The third aspect of the present invention provides an application of the preparation method of the first aspect or the distiller's grains dietary fiber of the second aspect, wherein the application is one or more of the following:

[0017] (1) Application in the preparation of products with hypoglycemic activity;

[0018] (2) Use in the preparation of products that help maintain healthy blood sugar levels;

[0019] (3) Use in the preparation of products capable of lowering fasting blood sugar levels;

[0020] (4) Application in the preparation of products capable of improving glucose tolerance;

[0021] (5) Application in the preparation of products capable of improving insulin resistance.

[0022] Furthermore, the product is food, health product, medicine or feed.

[0023] The present invention has the following beneficial effects:

[0024] 1. The present invention simplifies the production process of distiller's grains dietary fiber. Most impurities in the distiller's grains are removed through alkaline soaking and sodium chlorite bleaching, resulting in high-purity dietary fiber. The resulting product is whitish to pale yellow in color, has no noticeable odor, and exhibits excellent water-holding and expansion properties, making it highly suitable for use as a functional food additive.

[0025] 2. The production method of the vinasse dietary fiber of the present invention is that the entire production process is carried out under normal pressure, and conventional chemical equipment can meet the requirements, and the yield is considerable, with valuable economic benefits, and it is easy to realize industrial production.

[0026] 3. The distiller's grains dietary fiber prepared by the present method can effectively improve hyperglycemia (type 2 diabetes) in obese diabetic mice, lower fasting blood glucose levels, and improve glucose tolerance and insulin resistance. Its hypoglycemic activity is dose-dependent and can be used to prepare functional foods, health products, medicines, or feeds with hypoglycemic effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the fasting blood glucose change curve of mice.

[0028] Figure 2 This is the oral glucose tolerance curve of mice.

[0029] Figure 3 It is the area under the curve (AUC) of oral glucose tolerance test in mice.

[0030] Figure 4 is the fasting insulin (FINS) level of mice.

[0031] Figure 5 is the insulin sensitivity (HOMA-IR) level of mice. DETAILED DESCRIPTION

[0032] Unless otherwise defined, all scientific and technical terms used in the present invention have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention relates.

[0033] The disclosures of various publications, patents, and published patent specifications cited herein are incorporated by reference in their entirety.

[0034] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all commercially available conventional products.

[0035] Example 1 Preparation method of vinasse dietary fiber

[0036] 1) Alkali soaking: The lees were passed through a 20-mesh sieve to remove impurities and retain the rice husks. The rice husks were then soaked in a 5% (w / v) NaOH solution for 48 hours, with a mass ratio of rice husk to NaOH solution of 1:5. After soaking, the rice husks were repeatedly washed with water to remove the NaOH, and the precipitate was collected by filtration.

[0037] 2) Bleaching: Add 1-3% (w / v) NaClO2 solution to the precipitate, with a mass ratio of 1:5 between the precipitate and the NaClO2 solution. After mixing, adjust the pH to 4.6-5.5 with 10% (v / v) acetic acid. Heat to 70-80°C and stir to bleach for 1-3 hours. Repeat 1-2 times until the precipitate turns light yellow. Ensure ventilation during the bleaching process. After bleaching, rinse with water several times to remove the NaClO2 and collect the precipitate by filtration.

[0038] 3) Refining: add water to the precipitate and refine it, with the volume ratio of precipitate to water being 1:1. Pass the slurry through a 100-mesh filter and squeeze out the water.

[0039] 4) Drying and pulverizing: The precipitate is dried at 60° C. The dried material is pulverized, dried, and sieved to 80-100 mesh to obtain a distiller's grains dietary fiber product with a powdery appearance and a light yellow to slightly white color.

[0040] Example 2 Hypoglycemic Effect of Distillers Grains Dietary Fiber

[0041] C57BL / 6 mice were housed in a standard animal room under a 12-hour light cycle, 26±1°C, and 50-60% relative humidity, with free access to food and water. After a week of adaptive feeding, they were divided into two groups: a normal diet group (control group, n=12) and a high-fat diet group (model group, n=36). The normal diet group was fed a standard maintenance diet, while the high-fat diet group was fed a high-fat diet (HFD, 60% fat as energy source). Models were established after 16 weeks of feeding. Mice in the high-fat diet group received two intraperitoneal injections of STZ (100 mg / kg, pH 4.5, dissolved in 0.1 mmol / L pre-cooled citrate buffer). The control group received an intraperitoneal injection of citrate buffer. Mice were fasted for 12 hours before injection. Seven days after STZ injection, fasting blood glucose (FBG) was measured in the model group mice after a 12-hour fast. A FBG concentration above 11.1 mmol / L was considered a successful model. Mice with successful modeling were randomly divided into four groups: a normal control group (NC, normal diet, n=12), a type 2 diabetes control group (MD, high-fat diet, n=12), a high-dose distiller's grains fiber group (DF-H, HFD + 15% distiller's grains fiber, n=12), and a low-dose distiller's grains fiber group (DF-L, HFD + 5% distiller's grains fiber, n=12). The intervention lasted for 6 weeks. The mice's food intake and body weight were measured weekly, and blood glucose levels were measured every two weeks using a glucometer.

[0042] Example 3 Oral glucose tolerance test

[0043] Mice fasted overnight for 12 hours were gavaged with 1 g / kg glucose. Blood glucose levels were measured in the tail vein of the mice at 0, 15, 30, 60, and 120 minutes using a glucometer. The integrated area under the blood glucose curve (AUC) was calculated using Prism 9.0 software.

[0044] The fasting blood glucose (FBG) curve can be used to evaluate the hypoglycemic effect of distiller's grains dietary fiber. Figure 1 As shown in the figure, blood glucose levels remained stable in the NC group during the experiment, significantly increased in the MD group, and decreased significantly in the DF-H group. In the final week, fasting blood glucose levels in both the DF-L and DF-H groups were significantly lower than those in the MD group, with the DF-H group experiencing a more pronounced decrease. This suggests that distiller's grains dietary fiber can effectively lower blood glucose levels in diabetic mice in a dose-dependent manner.

[0045] The glucose tolerance test (OGTT) was used to evaluate the effect of distiller's grains dietary fiber on the glucose tolerance of diabetic mice. Figure 2 and Figure 3As shown. After oral gavage with glucose, the blood glucose level in the DF-H group was significantly lower than that in the MD and DF-L groups. Blood glucose began to decrease 30 minutes later, with the decrease being most pronounced in the DF-H group. The area under the curve (AUC) of the OGTT reflects the glucose metabolism capacity of mice. The AUC of diabetic mice was significantly higher than that of the NC group, indicating that the mice's glucose metabolism capacity was impaired. Compared with the MD group, the AUC of the DF-H group was significantly lower, indicating that high-dose distiller's grains dietary fiber intervention can improve glucose metabolism in diabetic mice.

[0046] Example 4 Fasting Insulin (FINS) Level Determination and Insulin Sensitivity (HOMA-IR) Calculation

[0047] Fasting insulin (FINS) levels were measured using a mouse insulin (INS) ELISA kit. 100 μl of insulin standard working solution and mouse serum test sample (10-fold dilution) were added to each reaction well, the plate was sealed and incubated at 37°C for 90 minutes. The liquid was discarded, the plate was shaken dry, and 100 μl of biotin-labeled insulin antibody working solution was added to each reaction well, the plate was sealed and incubated at 37°C for 60 minutes. The plate was washed four times, and 100 μl of HRP-labeled streptavidin working solution was added, the plate was sealed and incubated at 37°C for 30 minutes. The plate was washed four times, and 90 μl of color developer (protected from light) was added to the reaction well. The plate was sealed and color developed at 37°C for approximately 15 minutes in the dark. 50 μl of stop solution was then added, and the OD value was immediately measured using a microplate reader at a wavelength of 450 nm (within 5 minutes). The insulin concentration was calculated based on the standard curve and multiplied by the dilution factor. HOMA-IR was calculated as follows: insulin resistance index (HOMA-IR) = fasting plasma glucose (FPG, mmol / L) × fasting insulin (FINS, μU / mL) / 22.5.

[0048] Serum insulin levels can reflect pancreatic islet function, and the results are as follows Figure 4 As shown. The FINSA concentration of mice in the MD group was significantly lower than that in the NC group, indicating that the pancreatic islet function of diabetic mice was impaired. The FINS level in the DF-H group was significantly higher than that in the MD group, indicating that the pancreatic islet function of mice in the DF-H group was significantly improved. HOMA-IR is an indicator used to evaluate the level of insulin resistance in individuals. Figure 5 Compared with the MD group, the HOMA-IR index of the DF-L and DF-H groups was significantly reduced, and it was more obvious in the DF-H group.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing distiller's grains dietary fiber with hypoglycemic activity, characterized in that: The preparation method comprises the steps of alkali soaking, bleaching, refining and drying and crushing.

2. The preparation method according to claim 1, characterized in that The preparation method comprises the following steps: (1) Alkali soaking: The lees were passed through a 20-mesh sieve to remove impurities and retain the rice husks. The rice husks were soaked in a 5% (w / v) NaOH solution for 48 hours, with the mass ratio of rice husks to NaOH solution being 1:

5. After the soaking, the NaOH was removed by repeated washing with water, and the first precipitate was collected by filtration. (2) Bleaching: Add 1-3% (w / v) NaClO2 solution to the first precipitate, with the mass ratio of the first precipitate to the NaClO2 solution being 1:

5. After mixing, adjust the pH to 5 with 10% (v / v) acetic acid, heat to 70-80°C, stir and decolorize for 1-3 hours, and collect the second precipitate by filtration; (3) Refining: Grind the second precipitate with water, with the volume ratio of the second precipitate to water being 1:

1. Pass the slurry through a 100-mesh filter, squeeze and drain the water to obtain the third precipitate. (4) Drying and pulverizing: drying the third precipitate at 60° C., pulverizing, drying, and sieving the dried material to 80-100 mesh, and obtaining a distiller's grains dietary fiber product.

3. The preparation method according to claim 2, characterized in that In step (2), the stirring and decolorization step is repeated 1 to 2 times until the precipitate becomes light yellow, and then washed with water several times to remove NaClO2.

4. The preparation method according to any one of claims 1 to 3, characterized in that The lees are white wine lees or yellow wine lees.

5. Dietary fiber obtained by the preparation method according to any one of claims 1 to 4.

6. The use of the preparation method according to any one of claims 1 to 4 or the vinasse dietary fiber according to claim 5, wherein the use is one or more of the following: (1) Application in the preparation of products with hypoglycemic activity; (2) Use in the preparation of products that help maintain healthy blood sugar levels; (3) Use in the preparation of products capable of lowering fasting blood sugar levels; (4) Application in the preparation of products capable of improving glucose tolerance; (5) Application in the preparation of products capable of improving insulin resistance.

7. The use according to claim 6, characterized in that The product is food, health product, medicine or feed.

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