Modified wheat bran dietary fiber and method for preparing the same

Abstract

The application discloses modified wheat bran dietary fiber and a preparation method thereof, and the preparation method comprises the following steps: low-temperature plasma pretreatment is performed on wheat bran; the low-temperature plasma pretreated wheat bran is washed with water and then subjected to high-pressure cooking treatment; the high-pressure cooking treated wheat bran is subjected to starch removal and protease hydrolysis treatment, centrifugal separation is performed to obtain supernatant and solid insoluble matter; acid xylanase and arabinofuranosidase are added into the solid insoluble matter, and semi-solid enzymolysis is performed. On the basis of the process of removing starch and protein by enzymolysis to prepare dietary fiber, the semi-solid enzymolysis modification is further performed according to the characteristics that the wheat bran dietary fiber is rich in arabinoxylan. Meanwhile, the low-temperature plasma is combined to pretreat the wheat bran, the content of water-soluble dietary fiber is increased, and the physical and chemical functional properties of the dietary fiber are improved.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a modified wheat bran dietary fiber and its preparation method. Background Technology

[0002] Wheat bran is rich in dietary fiber, making it an ideal source of dietary fiber, with a content of 35%–50%. The ratio of insoluble dietary fiber (IDF) to soluble dietary fiber (SDF) is approximately 9:1. Due to its high proportion of IDF and rough texture, it is currently consumed primarily as low-value animal feed, lacking in more advanced products and resulting in resource waste. Existing research indicates that soluble dietary fiber can reduce fat digestibility; has better blood sugar control; and possesses strong gel-forming and emulsifying properties, making it easily incorporated into food. Dietary fiber with an SDF content of 10% or higher can be considered high-quality dietary fiber.

[0003] Currently, the main methods for preparing dietary fiber from wheat bran include biological, chemical, and physical methods. Among them, the enzymatic method is a commonly used method due to its advantages such as mild conditions, minimal loss of nutrients, high safety, and relatively simple and easy-to-operate equipment. Existing technologies for preparing dietary fiber using the enzymatic method primarily involve enzymatic hydrolysis to remove starch and protein. For example, Chinese invention patent CN 104824682A discloses a method for preparing dietary fiber from wheat bran, which has the following drawbacks: relying solely on enzymatic hydrolysis to remove starch and protein from wheat bran results in low purity dietary fiber, low SDF content in the product, and poor functional properties of the dietary fiber.

[0004] Novel physical processing modification technology combined with biological enzymatic modification technology can effectively improve product properties. Currently, there are no publicly available literature reports on low-temperature plasma pretreatment of wheat bran combined with enzymatic modification of wheat bran dietary fiber. Summary of the Invention

[0005] In view of the above-mentioned shortcomings in the prior art, the purpose of this invention is to provide a modified wheat bran dietary fiber and its preparation method.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0007] A method for preparing modified wheat bran dietary fiber is provided, characterized by comprising the following steps:

[0008] Step 1: Perform low-temperature plasma pretreatment on wheat bran for 10-60 seconds and 0.25-1.00 A.

[0009] Step 2: After washing the wheat bran pretreated with low-temperature plasma, it is subjected to high-pressure cooking.

[0010] Step 3: The wheat bran after high-pressure cooking is subjected to destarch and deproteinization treatment, and centrifuged to separate the supernatant and solid insoluble matter;

[0011] Step 4: Add acidic xylanase and arabinofuranase to the solid insoluble matter for semi-solid enzymatic hydrolysis; wherein the water content is 10-40% by mass, the hydrolysis temperature is 45-65℃, the hydrolysis time is 0.5-3.5h, and the pH value is 4-6.

[0012] Step 5: Mix the supernatant from step 3 with the enzymatic hydrolysis product from step 4, and then perform enzyme inactivation, alcohol precipitation, centrifugation, and drying to obtain modified wheat bran dietary fiber.

[0013] Furthermore, in step 2, the pressure cooking process involves a material-to-liquid ratio of 1:15 to 1:20, a pH value of 4.5 to 5.5, a treatment temperature of 115 to 125°C, and a treatment time of 20 to 40 minutes.

[0014] Further, the specific method of step 3 is as follows: after the wheat bran treated by high pressure is allowed to stand and cool down, 0.1-0.3% of α-amylase is added, and the enzymatic hydrolysis reaction is carried out at 40-60℃ for 50 min. The pH is adjusted to 8-10, and 2-4% of alkaline protease is added. The enzymatic hydrolysis reaction is carried out at 40-60℃ for 2-4 h. After the enzyme is inactivated by boiling water bath, the mixture is centrifuged to obtain the supernatant and the precipitated solid insoluble matter.

[0015] Further, in step 4, the amount of acidic xylanase added is 0.002% to 0.006% by mass, and the amount of arabinofuranase added is 0.005‰ to 0.015‰ by mass.

[0016] The beneficial effects of this invention are as follows:

[0017] This invention, based on the process of enzymatically removing starch and protein to prepare dietary fiber, further utilizes the characteristic of wheat bran dietary fiber being rich in arabinoxylan to perform semi-solid enzymatic modification of insoluble dietary fiber using acidic xylanase and arabinofuranase. Simultaneously, low-temperature plasma pretreatment of wheat bran is combined to increase the content of water-soluble dietary fiber and improve the physicochemical properties of the dietary fiber. Detailed Implementation

[0018] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0019] Example 1

[0020] (1) Low-temperature plasma treatment was performed on wheat bran that had been crushed through a 60-mesh sieve for 10 seconds and 0.25 A current.

[0021] (2) The wheat bran pretreated with low-temperature plasma was washed and then subjected to high-pressure cooking.

[0022] The pressure cooking process involved a material-to-liquid ratio of 1:15, with the pH adjusted to 4.5 using citric acid. The pressure cooking temperature was 115℃, and the time was 20 minutes.

[0023] (3) The wheat bran after high-pressure cooking is subjected to two steps of destarching and deproteinization, and the supernatant and solid insoluble matter are separated by centrifugation.

[0024] After cooling to a standstill, 0.1% α-amylase was added, and the enzymatic hydrolysis reaction was carried out at 40℃ for 50 min. The pH was adjusted to 8 with NaOH, and 2% alkaline protease was added, followed by enzymatic hydrolysis at 40℃ for 2 h. After enzyme inactivation treatment by boiling water bath, centrifugation was performed to obtain the supernatant and the precipitated solid insoluble matter.

[0025] (4) Add acidic xylanase and arabinofuranase to the solid insoluble matter to carry out semi-solid enzymatic hydrolysis;

[0026] The water content was 10%, the enzymatic hydrolysis temperature was 45℃, the enzymatic hydrolysis time was 0.5h, the pH value was 4, the acidic xylanase addition was 0.002%, and the arabinofuranase addition was 0.005‰.

[0027] Mix the supernatant from (3) with the enzymatic hydrolysis product from (4), inactivate the enzyme in a boiling water bath for 15 min, precipitate with 4 times the volume of anhydrous ethanol, let stand for 12 h, centrifuge at 4000 rap / min for 10 min and discard the supernatant, and dry the solid insoluble matter at 60℃ for 4 h to obtain modified wheat bran dietary fiber.

[0028] Example 2

[0029] (1) Low-temperature plasma treatment was performed on wheat bran that had been crushed through a 60-mesh sieve for 40 seconds and 0.6A.

[0030] (2) The wheat bran pretreated with low-temperature plasma was washed and then subjected to high-pressure cooking.

[0031] The pressure cooking process involved a material-to-liquid ratio of 1:17, with the pH adjusted to 5.0 using citric acid. The pressure cooking temperature was 120℃, and the time was 30 minutes.

[0032] (3) The wheat bran after high-pressure cooking is subjected to two steps of destarching and deproteinization, and the supernatant and solid insoluble matter are separated by centrifugation.

[0033] After cooling to a standstill, 0.2% α-amylase was added, and the enzymatic hydrolysis reaction was carried out at 50℃ for 50 min. The pH was adjusted to 9 with NaOH, and 3% alkaline protease was added, followed by enzymatic hydrolysis at 50℃ for 3 h. After enzyme inactivation treatment by boiling water bath, centrifugation was performed to obtain the supernatant and the precipitated solid insoluble matter.

[0034] (4) Add acidic xylanase and arabinofuranase to the solid insoluble matter to carry out semi-solid enzymatic hydrolysis;

[0035] Water addition 25%, enzymatic hydrolysis temperature 55℃, enzymatic hydrolysis time 2.0h, pH value 5, acidic xylanase addition 0.004%, arabinofuranylase addition 0.010‰;

[0036] Mix the supernatant from (3) with the enzymatic hydrolysis product from (4), inactivate the enzyme in a boiling water bath for 15 min, precipitate with 4 times the volume of anhydrous ethanol, let stand for 12 h, centrifuge at 4000 rap / min for 10 min and discard the supernatant, and dry the solid insoluble matter at 60℃ for 4 h to obtain modified wheat bran dietary fiber.

[0037] Example 3

[0038] (1) Low-temperature plasma treatment was performed on wheat bran that had been crushed through a 60-mesh sieve for 60 seconds and 1.00 A current.

[0039] (2) The wheat bran pretreated with low-temperature plasma was washed and then subjected to high-pressure cooking.

[0040] The pressure cooking process involved a material-to-liquid ratio of 1:20, with the pH adjusted to 5.5 using citric acid. The pressure cooking temperature was 125℃, and the time was 40 minutes.

[0041] (3) The wheat bran after high-pressure cooking is subjected to two steps of destarching and deproteinization, and the supernatant and solid insoluble matter are separated by centrifugation.

[0042] After cooling to a standstill, 0.3% α-amylase was added, and the enzymatic hydrolysis reaction was carried out at 60℃ for 50 min. The pH was adjusted to 10 with NaOH, and 4% alkaline protease was added, followed by enzymatic hydrolysis at 60℃ for 4 h. After enzyme inactivation treatment by boiling water bath, centrifugation was performed to obtain the supernatant and the precipitated solid insoluble matter.

[0043] (4) Add acidic xylanase and arabinofuranase to the solid insoluble matter to carry out semi-solid enzymatic hydrolysis;

[0044] The water content was 40%, the enzymatic hydrolysis temperature was 65℃, the enzymatic hydrolysis time was 3.5h, the pH value was 6, the acidic xylanase addition was 0.006%, and the arabinofuranase addition was 0.015‰.

[0045] Mix the supernatant from (3) with the enzymatic hydrolysis product from (4), inactivate the enzyme in a boiling water bath for 15 min, precipitate with 4 times the volume of anhydrous ethanol, let stand for 12 h, centrifuge at 4000 rap / min for 10 min and discard the supernatant, and dry the solid insoluble matter at 60℃ for 4 h to obtain modified wheat bran dietary fiber.

[0046] Comparative Example 1

[0047] (1) High-pressure cooking treatment of wheat bran that has been crushed through a 60-mesh sieve;

[0048] The pressure cooking process involved a material-to-liquid ratio of 1:17, with the pH adjusted to 5.0 using citric acid. The pressure cooking temperature was 120℃, and the time was 30 minutes.

[0049] (2) The wheat bran after high-pressure cooking is subjected to two steps of destarching and deproteinization.

[0050] Add 0.2% α-amylase and hydrolyze at 50℃ for 50 min. Adjust the pH to 9 with NaOH, add 3% alkaline protease, and hydrolyze at 50℃ for 3 h to obtain wheat bran dietary fiber.

[0051] Comparative Example 2

[0052] (1) Low-temperature plasma treatment was performed on wheat bran that had been crushed through a 60-mesh sieve for 40 seconds and 0.6A.

[0053] (2) The wheat bran pretreated with low-temperature plasma was washed and then subjected to high-pressure cooking.

[0054] The pressure cooking process involved a material-to-liquid ratio of 1:17, with the pH adjusted to 5.0 using citric acid. The pressure cooking temperature was 120℃, and the time was 30 minutes.

[0055] (3) The wheat bran after high-pressure cooking is subjected to two steps of destarching and deproteinization.

[0056] Add 0.2% α-amylase and hydrolyze at 50℃ for 50 min. Adjust the pH to 9 with NaOH, add 3% alkaline protease, and hydrolyze at 50℃ for 3 h to obtain wheat bran dietary fiber.

[0057] Comparative Example 3

[0058] (1) High-pressure cooking treatment of wheat bran that has been crushed through a 60-mesh sieve;

[0059] The pressure cooking process involved a material-to-liquid ratio of 1:17, with the pH adjusted to 5.0 using citric acid. The pressure cooking temperature was 120℃, and the time was 30 minutes.

[0060] (2) The wheat bran after high-pressure cooking is subjected to two steps of destarching and deproteinization, and the supernatant and solid insoluble matter are separated by centrifugation.

[0061] After cooling to a standstill, 0.2% α-amylase was added, and the enzymatic hydrolysis reaction was carried out at 50℃ for 50 min. The pH was adjusted to 9 with NaOH, and 3% alkaline protease was added, followed by enzymatic hydrolysis at 50℃ for 3 h. After enzyme inactivation treatment by boiling water bath, centrifugation was performed to obtain the supernatant and the precipitated solid insoluble matter.

[0062] (3) Add acidic xylanase to the solid insoluble matter to carry out semi-solid enzymatic hydrolysis;

[0063] Water addition 25%, enzymatic hydrolysis temperature 55℃, enzymatic hydrolysis time 2.0h, pH value 5, acidic xylanase addition 0.004%;

[0064] Mix the supernatant from (3) with the enzymatic hydrolysis product from (4), inactivate the enzyme in a boiling water bath for 15 min, precipitate with 4 times the volume of anhydrous ethanol, let stand for 12 h, centrifuge at 4000 rap / min for 10 min and discard the supernatant, and dry the solid insoluble matter at 60℃ for 4 h to obtain modified wheat bran dietary fiber.

[0065] Comparative Example 4

[0066] (1) High-pressure cooking treatment of wheat bran that has been crushed through a 60-mesh sieve;

[0067] The pressure cooking process involved a material-to-liquid ratio of 1:17, with the pH adjusted to 5.0 using citric acid. The pressure cooking temperature was 120℃, and the time was 30 minutes.

[0068] (2) The wheat bran after high-pressure cooking is subjected to two steps of destarching and deproteinization, and the supernatant and solid insoluble matter are separated by centrifugation.

[0069] After cooling to a standstill, 0.2% α-amylase was added, and the enzymatic hydrolysis reaction was carried out at 50℃ for 50 min. The pH was adjusted to 9 with NaOH, and 3% alkaline protease was added, followed by enzymatic hydrolysis at 50℃ for 3 h. After enzyme inactivation treatment by boiling water bath, centrifugation was performed to obtain the supernatant and the precipitated solid insoluble matter.

[0070] (3) Add acidic xylanase and arabinofuranase to the solid insoluble matter to carry out semi-solid enzymatic hydrolysis;

[0071] Water addition 25%, enzymatic hydrolysis temperature 55℃, enzymatic hydrolysis time 2.0h, pH value 5, acidic xylanase addition 0.004%, arabinofuranylase addition 0.010‰;

[0072] Mix the supernatant from (3) with the enzymatic hydrolysis product from (4), inactivate the enzyme in a boiling water bath for 15 min, precipitate with 4 times the volume of anhydrous ethanol, let stand for 12 h, centrifuge at 4000 rap / min for 10 min and discard the supernatant, and dry the solid insoluble matter at 60℃ for 4 h to obtain modified wheat bran dietary fiber.

[0073] The experimental data on the physicochemical functional properties of wheat bran dietary fiber obtained in Examples 1-3 and Comparative Examples 1-4 are shown in Table 1-2 below:

[0074] Table 1

[0075]

[0076]

[0077] Table 2

[0078]

[0079] As shown in Table 1-2, the combined use of low-temperature plasma pretreatment of wheat bran and semi-solid enzymatic hydrolysis technology helps to improve the functional properties of wheat bran dietary fiber, especially the glucose adsorption capacity, cholesterol adsorption capacity, bile salt binding capacity and total antioxidant activity of water-soluble dietary fiber are significantly improved; the water-soluble dietary fiber content of wheat bran is increased to more than 14%, which meets the content requirements of high-quality dietary fiber.

[0080] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0081] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing modified wheat bran dietary fiber, characterized in that, Includes the following steps: Step 1: Perform low-temperature plasma pretreatment on wheat bran for 10-60 seconds and 0.25-1.00 A. Step 2: After washing the wheat bran pretreated with low-temperature plasma, it is subjected to high-pressure cooking. Step 3: The wheat bran after high-pressure cooking is subjected to destarch and deproteinization treatment, and centrifuged to separate the supernatant and solid insoluble matter; Step 4: Add acidic xylanase and arabinofuranase to the solid insoluble matter for semi-solid enzymatic hydrolysis; wherein the water content is 10-40% by mass, the hydrolysis temperature is 45-65℃, the hydrolysis time is 0.5-3.5h, and the pH value is 4-6. Step 5: Mix the supernatant from step 3 with the enzymatic hydrolysis product from step 4, and then perform enzyme inactivation, alcohol precipitation, centrifugation, and drying to obtain modified wheat bran dietary fiber.

2. The method for preparing modified wheat bran dietary fiber according to claim 1, characterized in that, In step 2, the pressure cooking process involves a material-to-liquid ratio of 1:15 to 1:20, a pH value of 4.5 to 5.5, a treatment temperature of 115 to 125°C, and a treatment time of 20 to 40 minutes.

3. The method for preparing modified wheat bran dietary fiber according to claim 1, characterized in that, The specific method for step 3 is as follows: After the wheat bran treated by high pressure cooking is allowed to stand and cool down, 0.1-0.3% of α-amylase is added, and the enzymatic hydrolysis reaction is carried out at 40-60℃ for 50 min. The pH is adjusted to 8-10, and 2-4% of alkaline protease is added. The enzymatic hydrolysis reaction is carried out at 40-60℃ for 2-4 h. After the enzyme is inactivated by boiling water bath, the mixture is centrifuged to obtain the supernatant and the precipitated solid insoluble matter.

4. The method for preparing modified wheat bran dietary fiber according to claim 1, characterized in that, In step 4, the amount of acidic xylanase added is 0.002% to 0.006% by mass, and the amount of arabinofuranase added is 0.005‰ to 0.015‰ by mass.

5. Modified wheat bran dietary fiber prepared by the method of any one of claims 1-4.

Images