Preparation method of oat bran insoluble dietary fiber with excellent physical and chemical properties

Abstract

The invention relates to a preparation method of oat bran insoluble dietary fibers with excellent physical and chemical properties. The preparation method comprises the following steps: preparing defatted oat bran powder; putting the prepared defatted oat bran powder into a beaker, adding an ethanol solution, uniformly mixing, carrying out ultrasonic treatment, removing the ethanol solution, desugaring, and drying overnight; preparing oat bran insoluble dietary fibers: taking 3g of oat bran insoluble dietary fibers, flatly laying the oat bran insoluble dietary fibers in a plate, and placing the plate in low-temperature plasma for modification treatment; weighing modified insoluble dietary fibers, adding distilled water, adjusting the pH value to 6.0, adding helicase, magnetically stirring at 35 DEG C for 1 hour, and boiling for enzyme deactivation; and cooling to room temperature, centrifuging, washing with water, centrifuging again to obtain a precipitate, and freeze-drying to obtain the insoluble dietary fiber with the oil holding capacity of 3.42 + / -0.027 g / g. After the prepared oat bran insoluble dietary fiber is digested in vitro, the DPPH and ABTS < + > removing capacity of the oat bran insoluble dietary fiber is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of food and dietary fiber modification, in particular to a method for preparing oat bran insoluble dietary fiber with excellent physical and chemical properties, and is a method for improving the physical and chemical properties of oat bran insoluble dietary fiber. Background Art

[0002] Oat bran is the main by-product of oat processing, accounting for about 50% of the whole oat. The rich dietary fiber content of oat bran makes it have a wide range of application potential in the food industry, especially in improving the nutritional value and health benefits of food. Insoluble dietary fiber is the main component of natural dietary fiber. Numerous studies have shown that insoluble dietary fiber has the functions of lowering blood sugar, lowering blood lipids and regulating intestinal flora. However, due to the rough taste, low solubility and poor quality of insoluble dietary fiber, its direct application in food will reduce the taste value of the food itself. In addition, the natural insoluble dietary fiber has a large molecular weight and a compact structure, which affects its physical, chemical and functional properties and hinders its further application. Therefore, modifying insoluble dietary fiber is a necessary means to improve its application value. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing insoluble dietary fiber from oat bran with excellent physical and chemical properties. The method for preparing insoluble dietary fiber from oat bran with excellent physical and chemical properties is used to solve the problem of poor physical and chemical properties of insoluble dietary fiber from oat bran in the prior art and increase the added value of oat bran.

[0004] In order to achieve the above object, the specific technical scheme adopted by the present invention is as follows: the preparation method of the insoluble dietary fiber of oat bran with excellent physical and chemical properties comprises the following steps: Step 1, preparing defatted oat bran powder: taking dried oat bran, crushing and sieving it with a grinder, adding it to petroleum ether and ultrasonically defatting it three times, and drying it to obtain oat bran powder; Step 2: Place the defatted oat bran powder prepared in step 1 in a beaker, add 85% ethanol solution, mix well, and perform ultrasonic treatment to remove the ethanol solution for 3 times; after desugaring, place the powder in a 40°C oven and dry overnight; Step 3, preparing oat bran insoluble dietary fiber: sieve the desugared oat bran powder prepared in step 2, add distilled water at a solid-liquid ratio of 1:30, adjust the pH to 6.0, add high-temperature resistant α-amylase, and stir magnetically at 95°C for 2 h; adjust the pH to 9.0, add alkaline protease, and stir magnetically at 60°C for 2 h; adjust the pH to 4.5, add amyloglucosidase, stir magnetically at 60°C for 1 h, and boil to inactivate the enzyme; after cooling to room temperature, centrifuge the mixture at 4000 r / min for 20 min, remove the supernatant, wash the precipitate with water, centrifuge to obtain the precipitate, and freeze-dry; the amount of high-temperature resistant α-amylase added is 2% of the mass of the desugared oat bran powder, the amount of alkaline protease added is 2% of the mass of the desugared oat bran powder, and the amount of amyloglucosidase added is 30 ul per gram of desugared oat bran powder; Step 4: Take 3 g of the above-prepared insoluble dietary fiber from oat bran and spread it in a plate with a diameter of 90 ml, and place the plate in a low-temperature plasma for modification; the plate spacing of the low-temperature plasma is set to 40 mm, the high-voltage discharge voltage is set to 90 kV, the discharge frequency is set to 50 Hz, the discharge duration is set to 60 s, the discharge interval time is set to 10 s, and the number of discharges is set to 30 times; Step 5: Weigh the modified insoluble dietary fiber prepared in step 4, add distilled water, adjust the pH to 6.0, add snail enzyme, stir magnetically at 35°C for 1 h, boil to inactivate the enzyme, and the amount of snail enzyme added is 3.5% of the mass of the modified insoluble dietary fiber weighed in this step; after cooling to room temperature, centrifuge the mixture at 4000 r / min for 20 min; remove the supernatant, wash the precipitate with water, obtain the precipitate by centrifugation, and freeze-dry. The obtained insoluble dietary fiber has an oil holding capacity of 3.42±0.027 g / g, a nitrite adsorption capacity of 1990.36±0.64 ug / g, a glucose adsorption capacity of 23.93±0.32 mg / g, and a cation exchange capacity of 3.85-9.56.

[0005] In step 1 of the above scheme, the speed of the pulverizer is 10000 r / min, and the time is 5 s-10 s; the mesh size of the sieve is 60 meshes.

[0006] During the degreasing in step 1 of the above scheme, 2000 mL of petroleum ether was used for every 500 g of oat bran powder, the ultrasonic power was 100 W, and the degreasing time was 5 h each time.

[0007] In step 2 of the above scheme, the solid-liquid ratio of defatted oat bran powder to ethanol is 1:10.

[0008] In step 2 of the above scheme, the ultrasonic power is 100 W and the ultrasonic time is 1 h each time.

[0009] The speed of magnetic stirring in step 3 of the above scheme is 1000 r / min.

[0010] The washing condition in step 3 of the above scheme is 80°C hot water, and the washing is thorough five times.

[0011] In step 5 of the above scheme, the freeze-drying temperature is -100 to -140°C, and the freeze-drying time is 10 h to 12 h. Beneficial Effects

[0012] 1. The present invention is the first to modify the insoluble dietary fiber of oat bran, a common oat byproduct, by using low-temperature plasma combined with snail enzyme method, and finally obtain an insoluble dietary fiber of oat bran with excellent physical and chemical properties by adjusting the preparation process. After modification, the insoluble dietary fiber presents loose and porous structural characteristics, more carboxyl groups and hydroxyl groups are exposed in the structure, and the overall particle size is reduced. These structural characteristics give the insoluble dietary fiber of oat bran excellent physical and chemical properties, which can improve the comprehensive utilization of oat byproducts.

[0013] 2. The present invention provides a method for improving the physical and chemical properties of insoluble dietary fiber, which has the advantages of simple extraction process, low energy consumption, short time, high extraction rate, and clean and pollution-free production process.

[0014] 3. The present invention improves the oil holding capacity of insoluble dietary fiber, and its application in the food industry can significantly improve the physical and chemical properties of products.

[0015] 4. The present invention improves the oil holding capacity (3.42±0.027 g / g), nitrite adsorption capacity (1990.18±0.64 ug / g), glucose adsorption capacity (23.93±0.32 mg / g), and antioxidant capacity of insoluble dietary fiber, and can be applied to food additives or health care products industry.

[0016] 5. After in vitro digestion, the DPPH and ABTS of the insoluble dietary fiber of oat bran prepared by the present invention are + The scavenging ability is significantly improved and can be applied to the food or health food industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The scanning electron microscope comparison diagrams of Example 1 and Comparative Examples 1-3; A is Comparative Example 1; B is Comparative Example 2; C is Comparative Example 3; D is Example 1, and the numbers in A1, B2, and C3 are 1. ×1000; 2. ×2000; and 3. ×5000.

[0018] Figure 2 The X-ray diffraction comparison diagram of Example 1 and Comparative Examples 1-3.

[0019] Figure 3 It is a comparison chart of the particle sizes of Example 1 and Comparative Examples 1-3.

[0020] Figure 4 It is a thermogravimetric analysis comparison diagram of Example 1 and Comparative Examples 1-3.

[0021] Figure 5 It is a comparison chart of the oil holding capacity of Example 1 and Comparative Examples 1-3.

[0022] Figure 6 It is a comparison chart of glucose adsorption capacity of Example 1 and Comparative Examples 1-3.

[0023] Figure 7 It is a comparison chart of the nitrite adsorption capacity of Example 1 and Comparative Examples 1-3.

[0024] Figure 8 It is a comparison chart of the cation exchange capacity of Example 1 and Comparative Examples 1-3.

[0025] Fig. 9 It is a comparison chart of the antioxidant capacity after simulated gastric digestion of Example 1 and Control Examples 1-3.

[0026] Fig.10 It is a comparison chart of the antioxidant capacity after simulated gastrointestinal digestion of Example 1 and Control Examples 1-3. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings: Example

[0028] Step 1. Prepare defatted oat bran powder: Take dry oat bran, crush and sieve it with a grinder, add 20,000 mL of petroleum ether to 500 g of oat bran powder, perform defatting treatment three times with 100 W ultrasound, each time for 5 h, and dry to obtain oat bran powder.

[0029] Step 2: Place the defatted oat bran powder prepared in step 1 in a beaker, add 85% ethanol solution at a solid-liquid ratio of 1:10, mix well, and ultrasonicate to remove the ethanol solution for 3 times. After desugaring, place the sample in a 40°C oven and dry overnight.

[0030] Step 3: Take the dried oat bran powder and pass it through a 60-mesh sieve, add distilled water at a solid-liquid ratio of 1:30, adjust the pH to 6.0, add thermostable α-amylase (2%, w / w), and bathe at 95 ℃ for 2 h; adjust the pH to 9.0, add alkaline protease (2%, w / w), and bathe at 60 ℃ for 2 h; adjust the pH to 4.5, add amyloglucosidase (30 ul / g), bathe at 60 ℃ for 1 h, and boil to inactivate the enzyme. After cooling to room temperature, centrifuge the mixture (4000 r / min, 20 min), remove the supernatant, disperse the precipitate in 80 ℃ hot water, wash it three times, centrifuge to obtain the precipitate, and dry it.

[0031] Step 4: Take 3 g of the above-prepared insoluble dietary fiber from oat bran and spread it on a plate, and place the sample in a low-temperature plasma for modification at 15-20°C. The low-temperature plasma instrument setting conditions are as follows: the plate spacing is set to 40 mm, the high-voltage discharge voltage is set to 90 kV, the discharge frequency is set to 50 Hz, the discharge duration is set to 60 s, the discharge interval time is set to 10 s, and the number of discharges is set to 30 times.

[0032] Step 5: Weigh the insoluble dietary fiber prepared in step 2, add distilled water at a solid-liquid ratio of 1:25, adjust the pH to 6.0, add snail enzyme (3.5%, w / w), and boil at 35 °C for 1 h to inactivate the enzyme. After cooling to room temperature, centrifuge the mixture (4000 r / min, 20 min). Remove the supernatant, disperse the precipitate in 80 °C hot water, wash it three times, centrifuge to obtain the precipitate, and freeze-dry it.

[0033] The insoluble skin dietary fiber of oat bran that has undergone combined modification has an oil holding capacity of 3.42±0.27 g / g, a glucose adsorption capacity of 23.93±0.32 mg / g, a sodium nitrite adsorption capacity of 1990.18±0.64 ug / g, a cation exchange capacity: the sodium hydroxide titration is (3.86-9.56±0.01), and an antioxidant capacity: after 2 h of gastric juice digestion: the ABTS clearance rate is 77.56%, and the DPPH clearance rate is 36.6%. After gastrointestinal juice digestion, the ABTS clearance rate is 84.34%, and the DPPH clearance rate is 52.04%.

[0034] Step 1. Prepare defatted oat bran powder: Take dry oat bran, crush and sieve it with a grinder, add 20,000 mL of petroleum ether to 500 g of oat bran powder, perform defatting treatment three times with 100 W ultrasound, each time for 5 h, and dry to obtain oat bran powder.

[0035] Step 2: Place the defatted oat bran powder prepared in step 1 in a beaker, add 85% ethanol solution at a solid-liquid ratio of 1:10, mix well, and ultrasonicate to remove the ethanol solution for 3 times. After desugaring, place the sample in a 40°C oven and dry overnight.

[0036] Step 3: Take dried oat bran powder (pass through a 60-mesh sieve), add distilled water at a solid-liquid ratio of 1:30, adjust the pH to 6.0, add thermostable α-amylase (2%, w / w), and bathe at 95 °C for 2 h; adjust the pH to 9.0, add alkaline protease (2%, w / w), and bathe at 60 °C for 2 h; adjust the pH to 4.5, add amyloglucosidase (30 ul / g), bathe at 60 °C for 1 h, and boil to inactivate the enzyme. After cooling to room temperature, centrifuge the mixture (4000 r / min, 20 min), remove the supernatant, disperse the precipitate in 80 °C hot water, wash it three times, centrifuge to obtain the precipitate, and freeze-dry it.

[0037] The insoluble dietary fiber of unmodified oat bran has an oil holding capacity of 2.32±0.05 g / g, a glucose adsorption capacity of 21.36±0.27 mg / g, a sodium nitrite adsorption capacity of 1967.85±1.34 ug / g, a cation exchange capacity: the sodium hydroxide titration is (3.87-11.04±0.05), and an antioxidant capacity: after 2 h of gastric juice digestion: the ABTS clearance rate is 70.99%, and the DPPH clearance rate is 32.24%. After gastrointestinal juice digestion, the ABTS clearance rate is 79.92%, and the DPPH clearance rate is 48.25%.

[0038] Step 1. Prepare defatted oat bran powder: Take dry oat bran, crush and sieve it with a grinder, add 20,000 mL of petroleum ether to 500 g of oat bran powder, perform defatting treatment three times with 100 W ultrasound, each time for 5 h, and dry to obtain oat bran powder.

[0039] Step 2: Place the defatted oat bran powder prepared in step 1 in a beaker, add 85% ethanol solution at a solid-liquid ratio of 1:10, mix well, and ultrasonicate to remove the ethanol solution for 3 times. After desugaring, place the sample in a 40°C oven and dry overnight.

[0040] Step 3: Take dried oat bran powder (pass through a 60-mesh sieve), add distilled water at a solid-liquid ratio of 1:30, adjust the pH to 6.0, add thermostable α-amylase (2%, w / w), and bathe at 95 °C for 2 h; adjust the pH to 9.0, add alkaline protease (2%, w / w), and bathe at 60 °C for 2 h; adjust the pH to 4.5, add amyloglucosidase (30 ul / g), bathe at 60 °C for 1 h, and boil to inactivate the enzyme. After cooling to room temperature, centrifuge the mixture (4000 r / min, 20 min), remove the supernatant, disperse the precipitate in 80 °C hot water, wash it three times, centrifuge to obtain the precipitate, and freeze-dry it.

[0041] Step 4: Weigh the insoluble dietary fiber prepared in step 1, add distilled water at a solid-liquid ratio of 1:25, adjust the pH to 6.0, add snail enzyme (3.5%, w / w), and boil at 35 °C for 1 h. After cooling to room temperature, centrifuge the mixture (4000 r / min, 20 min). Remove the supernatant, disperse the precipitate in 80 °C hot water, wash it three times, centrifuge to obtain the precipitate, and freeze-dry it.

[0042] The insoluble dietary fiber of oat bran modified with snail enzyme has an oil holding capacity of 2.94±0.06 g / g, a glucose adsorption capacity of 22.87±0.03 mg / g, a sodium nitrite adsorption capacity of 1980.72±0.57 ug / g, a cation exchange capacity: the sodium hydroxide titration is (3.89-10.68±0.05), and an antioxidant capacity: after 2 h of gastric juice digestion: the ABTS clearance rate is 77.13%, and the DPPH clearance rate is 33.84%. After gastrointestinal juice digestion, the ABTS clearance rate is 83.86%, and the DPPH clearance rate is 49.17%.

[0043] Step 1. Prepare defatted oat bran powder: Take dry oat bran, crush and sieve it with a grinder, add 20,000 mL of petroleum ether to 500 g of oat bran powder, perform defatting treatment three times with 100 W ultrasound, each time for 5 h, and dry to obtain oat bran powder.

[0044] Step 2: Place the defatted oat bran powder prepared in step 1 in a beaker, add 85% ethanol solution at a solid-liquid ratio of 1:10, mix well, and ultrasonicate to remove the ethanol solution for 3 times. After desugaring, place the sample in a 40°C oven and dry overnight.

[0045] Step 3: Take dried oat bran powder (pass through a 60-mesh sieve), add distilled water at a solid-liquid ratio of 1:30, adjust the pH to 6.0, add thermostable α-amylase (2%, w / w), and bathe at 95 °C for 2 h; adjust the pH to 9.0, add alkaline protease (2%, w / w), and bathe at 60 °C for 2 h; adjust the pH to 4.5, add amyloglucosidase (30 ul / g), bathe at 60 °C for 1 h, and boil to inactivate the enzyme. After cooling to room temperature, centrifuge the mixture (4000 r / min, 20 min), remove the supernatant, disperse the precipitate in 80 °C hot water, wash it three times, centrifuge to obtain the precipitate, and freeze-dry it.

[0046] Step 4: Take 3 g of the above-prepared insoluble dietary fiber from oat bran and spread it on a plate, and place the sample in plasma for modification. The plasma instrument setting conditions are as follows: the plate spacing is set to 40 mm, the high-voltage discharge voltage is set to 90 kV, the discharge frequency is set to 50 Hz, the discharge duration is set to 60 s, the discharge interval time is set to 10 s, and the number of discharges is set to 30 times.

[0047] The insoluble dietary fiber of oat bran modified by plasma has an oil holding capacity of 2.96±0.07 g / g, a glucose adsorption capacity of 22.4±0.25 mg / g, a sodium nitrite adsorption capacity of 1969.91±0.63 ug / g, a cation exchange capacity: the sodium hydroxide titration is (3.88-10.78±0.05), and an antioxidant capacity: after 2 h of gastric juice digestion: the ABTS clearance rate is 73.02%, and the DPPH clearance rate is 34.7%. After gastrointestinal juice digestion, the ABTS clearance rate is 82.90%, and the DPPH clearance rate is 50.54%.

[0048] Snail enzyme is a natural complex enzyme that contains more than 20 different enzymes including cellulase, pectinase and β-glucosidase. It has the advantages of easy access, low cost and convenient operation. Compared with single modification, low temperature plasma and snail enzyme combined modification of insoluble dietary fiber can more effectively improve the structure of insoluble dietary fiber, remove lignin, and release more phenolic compounds, so that the modified insoluble dietary fiber has good physical and chemical properties and functional characteristics.

Claims

1. A method for preparing insoluble dietary fiber from oat bran with excellent physical and chemical properties, characterized in that The steps include: Step 1, preparing defatted oat bran powder: taking dried oat bran, crushing and sieving it with a grinder, adding it to petroleum ether and ultrasonically defatting it three times, and drying it to obtain oat bran powder; Step 2: Place the defatted oat bran powder prepared in step 1 in a beaker, add 85% ethanol solution, mix well, and perform ultrasonic treatment to remove the ethanol solution for 3 times; after desugaring, place the powder in a 40°C oven and dry overnight; Step 3, preparing oat bran insoluble dietary fiber: sieve the desugared oat bran powder prepared in step 2, add distilled water at a solid-liquid ratio of 1:30, adjust the pH to 6.0, add high-temperature resistant α-amylase, and stir magnetically at 95°C for 2 h; adjust the pH to 9.0, add alkaline protease, and stir magnetically at 60°C for 2 h; adjust the pH to 4.5, add amyloglucosidase, stir magnetically at 60°C for 1 h, and boil to inactivate the enzyme; after cooling to room temperature, centrifuge the mixture at 4000 r / min for 20 min, remove the supernatant, wash the precipitate with water, centrifuge to obtain the precipitate, and freeze-dry; the amount of high-temperature resistant α-amylase added is 2% of the mass of the desugared oat bran powder, the amount of alkaline protease added is 2% of the mass of the desugared oat bran powder, and the amount of amyloglucosidase added is 30 ul per gram of desugared oat bran powder; Step 4: Take 3 g of the above-prepared insoluble dietary fiber from oat bran and spread it in a plate with a diameter of 90 ml, and place the plate in a low-temperature plasma for modification; the plate spacing of the low-temperature plasma is set to 40 mm, the high-voltage discharge voltage is set to 90 kV, the discharge frequency is set to 50 Hz, the discharge duration is set to 60 s, the discharge interval time is set to 10 s, and the number of discharges is set to 30 times; Step 5: Weigh the modified insoluble dietary fiber prepared in step 4, add distilled water, adjust the pH to 6.0, add snail enzyme, stir magnetically at 35°C for 1 h, boil to inactivate the enzyme, and the amount of snail enzyme added is 3.5% of the mass of the modified insoluble dietary fiber weighed in this step; after cooling to room temperature, centrifuge the mixture at 4000 r / min for 20 min; remove the supernatant, wash the precipitate with water, obtain the precipitate by centrifugation, and freeze-dry. The obtained insoluble dietary fiber has an oil holding capacity of 3.42±0.027 g / g, a nitrite adsorption capacity of 1990.36±0.64 ug / g, a glucose adsorption capacity of 23.93±0.32 mg / g, and a cation exchange capacity of 3.85-9.

56.

2. The method for preparing the insoluble dietary fiber from oat bran with excellent physical and chemical properties according to claim 1, characterized in that: In the step 1, the speed of the pulverizer is 10000 r / min, and the time is 5 s-10 s; the mesh size of the sieve is 60 meshes.

3. The method for preparing the insoluble dietary fiber from oat bran with excellent physical and chemical properties according to claim 2, characterized in that: During the degreasing in step 1, 2000 mL of petroleum ether is used for every 500 g of oat bran powder, the ultrasonic power is 100 W, and the degreasing time is 5 h each time.

4. The method for preparing the insoluble dietary fiber from oat bran with excellent physical and chemical properties according to claim 3, characterized in that: In the step 2, the solid-liquid ratio of the defatted oat bran powder to ethanol is 1:

10.

5. The method for preparing the insoluble dietary fiber from oat bran with excellent physical and chemical properties according to claim 4, characterized in that: In step 2, the ultrasonic power is 100 W, and the ultrasonic time is 1 h each time.

6. The method for preparing the insoluble dietary fiber from oat bran with excellent physical and chemical properties according to claim 5, characterized in that: The speed of the magnetic stirring in step 3 is 1000 r / min.

7. The method for preparing the insoluble dietary fiber from oat bran with excellent physical and chemical properties according to claim 6, characterized in that: The washing condition in step 3 is 80°C hot water, and the washing is performed five times.

8. The method for preparing the insoluble dietary fiber from oat bran with excellent physical and chemical properties according to claim 7, characterized in that: The freeze-drying temperature in step 5 is -100 to -140°C, and the freeze-drying time is 10 h to 12 h.

Images