Preparation method of wheat bran dietary fiber with emulsion stability

Abstract

The invention discloses a preparation method of wheat bran dietary fibers with emulsion stability, and relates to the technical field of agricultural waste recycling. The method has the advantages of small pollution, simplicity in operation and the like, and specifically comprises the following steps: fermenting wheat bran degreased and sterilized by normal hexane and a mixed bacteria solution of saccharomycetes powder and lactobacillus plantarum at 37 DEG C for 30-48 hours; and the sample is sterilized after being fermented. Dispersing the fermented wheat bran in a 0.1 M PBS (Phosphate Buffer Solution) (1: 5-1: 10 w / v), and sequentially adding amylase, papain and saccharifying enzyme to remove starch and protein; and carrying out enzyme deactivation on the fermented wheat bran feed liquid, washing, and drying to obtain the wheat bran dietary fiber. The obtained wheat bran dietary fiber has better emulsibility and has wide application prospects in the fields of food, feed, biological medicine and the like.

Description

Technical Field

[0001] The technology relates to the technical field of agricultural waste recycling, and in particular to a method for preparing emulsified stable wheat bran dietary fiber. Background Art

[0002] Wheat is a widely grown crop worldwide, and wheat bran, as the main byproduct of grain processing, is very abundant and is usually used as animal feed or brewing raw material, but its added value is relatively low, and there are shackles such as mixed ingredients, low purity, and poor enrichment of functional substances. In addition, if wheat bran is directly discarded as agricultural waste, it will also pollute the environment. Therefore, it is necessary to separate and purify its key components and apply them to the chemical, food and agricultural fields to achieve high-value utilization of wheat bran and improve its economic value and environmental benefits. Insoluble dietary fiber is the most critical component in wheat bran, accounting for more than 90% of the total fiber content. However, the depth of wheat bran in processing and comprehensive utilization is far from enough. Therefore, appropriate strategies are urgently needed to improve the efficiency and quality of wheat bran resource processing.

[0003] Existing strategies for bran resource processing mainly focus on physical and chemical methods, a process that is usually accompanied by problems such as resource depletion, wastewater discharge and pollution. Solid-state fermentation has become another effective processing strategy for bran resources due to its mild degradation mechanism. Solid-state fermentation technology promotes the release and transformation of nutrients in wheat bran through the metabolic activities of microorganisms, while destroying the fiber structure of wheat bran, releasing phenolic substances, improving their bioavailability, improving the quality of wheat bran, and obtaining biological products with specific nutritional value and functionality. In addition, solid-state fermentation is regarded as an excellent strategy for batch resource waste treatment due to its advantages such as low water activity, convenient operation and no residue, providing new ideas for the in-depth application of insoluble dietary fiber in the fields of fine chemicals, food and agriculture. It also enables the appropriate transformation of biomass resources and promotes the high-value processing and utilization of agricultural waste, which is in line with the current green, circular and sustainable development concepts. Summary of the invention

[0004] Technical problem to be solved: The purpose of the present invention is to provide a method for preparing emulsified stable wheat bran dietary fiber, which has the advantages of being mild, easy to operate, and leaving no residue, and improves the emulsification capacity of insoluble dietary fiber in wheat bran, improves the application prospects of wheat bran dietary fiber in the fields of food, feed, biomedicine, etc., and provides a green and convenient strategy for the transformation of bran biological resources.

[0005] Technical solution: A method for preparing emulsified stable wheat bran dietary fiber comprises the following steps:

[0006] Step 1: Ferment the wheat bran sterilized by defatting with n-hexane with a mixed bacterial solution of yeast powder and Lactobacillus plantarum at 37°C for 30-48 hours. Sterilize the fermented sample.

[0007] Step 2: Disperse the fermented wheat bran in step 1 in 0.1 M PBS buffer (1:5~1:10 w / v), and add amylase, papain and saccharifying enzyme in sequence to remove starch and protein.

[0008] Step 3: inactivate enzymes in the fermented wheat bran liquid, wash it and dry it to obtain wheat bran dietary fiber.

[0009] Preferably, in step 1, the material-liquid ratio of wheat bran to n-hexane is 1:8-1:10 (w / v).

[0010] Preferably, in the mixed suspension of yeast powder and Lactobacillus plantarum in step 1, the Lactobacillus plantarum solution is prepared by mixing Lactobacillus plantarum powder with MRS culture medium at a ratio of 1:400-1:800 (w / v) and culturing at 37°C for 15-20 h. The ratio of yeast powder to Lactobacillus plantarum suspension in the mixed culture solution is 1:80-1:100 (w / v).

[0011] Preferably, the ratio of wheat bran to mixed bacterial solution in step 1 is 1:1-1:2 (v / v).

[0012] Preferably, the enzyme addition procedure in the step 2 is as follows: the ratio of 4500-5000 U / mL amylase to the fermented wheat bran liquid is 2-4% v / v, and the reaction is carried out for 1.5-2 h at a temperature of 60-70 °C and a pH of 6.5-7.5; the ratio of 2000-2500 U / mL papain to the fermented wheat bran liquid is 1-2% v / v, and the reaction is carried out for 1-2 h at a temperature of 40-50 °C and a pH of 6.5-7.5; the ratio of saccharifying enzyme to the fermented wheat bran liquid is 1-2% v / v, and the reaction is carried out for 1-2 h at a temperature of 55 °C and a pH of 4.5-5.5.

[0013] Preferably, in step 3, the enzyme inactivation process needs to be heated to 90-100° C. and maintained for 20-40 min.

[0014] Preferably, the washing in step three is carried out with 95% ethanol, acetone and sterile water in a ratio of 1:5 to 1:10 (v / v).

[0015] Preferably, in the step 3, the drying temperature of the wheat bran is 40-50 ° C, and the moisture content of the wheat bran after drying is 10-15%. Beneficial Effects

[0016] The invention uses yeast and plant lactobacillus to mix and carry out solid-state fermentation to improve the emulsification of wheat bran insoluble dietary fiber, thereby obtaining a new dietary fiber suitable for food, feed and biomedicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The microstructure of the insoluble dietary fiber of wheat bran prepared in Examples 1 to 5 of the present invention;

[0018] Figure 2 The emulsification properties (A) and emulsion stability (B) of the wheat bran insoluble dietary fiber prepared in Examples 1 to 5 of the present invention. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings and specific examples, but it should not be construed as limiting the present invention. Without departing from the spirit and substance of the present invention, the modification or replacement of the method, steps or conditions of the present invention all belong to the scope of the present invention. The experimental methods and reagents without specifying the specific conditions in the examples are all in accordance with the conventional conditions in the art.

[0020] Example 1

[0021] Defatted and sterilized wheat bran was dispersed in 0.1 M PBS buffer (1:10 w / v). 5000 U / mL, 2% v / v amylase (70 °C, pH 7.0, 1.5 h), 2000 U / mL, 1% v / v papain (50 °C, pH7.0, 1 h) and 2500 U / mL, 1% v / v saccharifying enzyme (55 °C, pH 4.5, 1 h) were added in sequence. After the reaction was completed, the temperature was raised to inactivate, and the suspension was washed with 95% ethanol, acetone and sterile water in sequence. The residue was dried to obtain the control group (CK).

[0022] Example 2

[0023] The defatted and sterilized wheat bran was mixed with sterile water (solid-liquid ratio 1:1). Then, the sample was placed in a constant temperature incubator (37°C) for fermentation for 48h. After sterilization, the fermented wheat bran was dispersed in 0.1 M PBS buffer (1:10 w / v). 5000 U / mL, 2% v / v amylase (70 °C, pH 7.0, 1.5 h), 2000 U / mL, 1% v / v papain (50 °C, pH 7.0, 1 h) and 2500 U / mL, 1% v / v saccharifying enzyme (55 °C, pH 4.5, 1 h) were added in sequence. After the reaction was completed, the temperature was raised for inactivation, and the suspension was washed with 95% ethanol, acetone and sterile water in sequence. The residue was dried to obtain naturally fermented wheat bran dietary fiber (NF).

[0024] Example 3

[0025] The Lactobacillus plantarum powder was mixed with MRS medium at a ratio of 1:500 (w / v) and cultured at 37 °C for 16 h for pre-activation. The defatted and sterilized wheat bran was mixed with the pre-activated Lactobacillus plantarum suspension (solid-liquid ratio 1:1). Then, the sample was placed in a constant temperature incubator (37 °C) for fermentation for 48 h. After sterilization, the fermented wheat bran was dispersed in 0.1 M PBS buffer (1:10w / v). 5000 U / mL, 2% v / v amylase (70 °C, pH 7.0, 1.5 h), 2000 U / mL, 1% v / v papain (50 °C, pH 7.0, 1 h) and 2500 U / mL, 1% v / v saccharifying enzyme (55 °C, pH 4.5, 1 h) were added in sequence. After the reaction was completed, the temperature was raised for inactivation, and the suspension was washed with 95% ethanol, acetone and sterile water in sequence. The obtained residue is dried to obtain Lactobacillus plantarum fermented wheat bran dietary fiber (LF).

[0026] Example 4

[0027] Yeast powder and water were mixed at a ratio of 1:80 (w / v) to obtain a bacterial solution, and defatted and sterilized wheat bran was mixed with the yeast suspension (solid-liquid ratio 1:1). Then, the sample was placed in a constant temperature incubator (37 °C) for fermentation for 48 h. After sterilization, the fermented wheat bran was dispersed in 0.1 M PBS buffer (1:10 w / v). 5000 U / mL, 2% v / v amylase (70 °C, pH 7.0, 1.5 h), 2000 U / mL, 1% v / v papain (50 °C, pH 7.0, 1 h) and 2500 U / mL, 1% v / v saccharifying enzyme (55 °C, pH 4.5, 1 h) were added in sequence. After the reaction was completed, the temperature was raised for inactivation, and the suspension was washed with 95% ethanol, acetone and sterile water in sequence. The residue was dried to obtain yeast fermented wheat bran dietary fiber (YF).

[0028] Example 5

[0029] The Lactobacillus plantarum powder was mixed with MRS medium at a ratio of 1:500 (w / v) and cultured at 37 °C for 16 h for pre-activation. The yeast powder and Lactobacillus plantarum culture liquid were mixed at a ratio of 1:80 (w / v) to obtain a mixed culture liquid. The defatted and sterilized wheat bran was mixed with the mixed culture liquid (solid-liquid ratio 1:1). Then, the sample was placed in a constant temperature incubator (37 °C) for fermentation for 48 h. After sterilization, the fermented wheat bran was dispersed in 0.1 M PBS buffer (1:10 w / v). 5000 U / mL, 2% v / v amylase (70 °C, pH 7.0, 1.5 h), 2000 U / mL, 1% v / v papain (50 °C, pH 7.0, 1 h) and 2500 U / mL, 1% v / v saccharifying enzyme (55 °C, pH 4.5, 1 h) were added in sequence. After the reaction is completed, the temperature is raised to inactivate, and the suspension is washed with 95% ethanol, acetone and sterile water in sequence. The obtained residue is dried to obtain mixed fermentation fermented wheat bran dietary fiber (MF).

[0030] Performance tests were performed on Examples 1 to 5 and the prepared dietary fibers.

[0031] 1. Microstructure of insoluble dietary fiber from wheat bran under different fermentation modes Figure 1 Compared with CK, the surface of the fermented insoluble dietary fiber became disordered and complex, with flake and honeycomb structures, and the degree of fragmentation was more serious in the YF and MF groups. In addition, the MF group caused more significant damage to the surface of the insoluble dietary fiber, and the surface morphology became more porous and loose, which had a positive impact on its functional activity and performance.

[0032] 2. Emulsifying properties of wheat bran insoluble dietary fiber Figure 2 Emulsification ( Figure 2 A) The results show that the emulsification of insoluble dietary fiber is greatly improved after fermentation. Even natural fermentation can improve the emulsification of insoluble dietary fiber, but MF has the best emulsification performance, far exceeding the insoluble dietary fiber prepared by fermentation of a single strain. Emulsification stability ( Figure 2 B) The results showed that fermented insoluble dietary fiber exhibited good emulsification ability for peanut oil in both heating-cooling stages, and the emulsification stability of MF was much higher than that of other groups.

Claims

1. A method for preparing emulsion-stable wheat bran dietary fiber, characterized in that, Here are the steps: Step 1: Ferment the wheat bran sterilized by defatting with n-hexane with a mixed bacterial solution of yeast powder and Lactobacillus plantarum at 37 °C for 30-48 h. Sterilize the fermented sample.

2. Step 2: Disperse the fermented wheat bran in step 1 in 0.1 M PBS buffer (1:5~1:10 w / v), and add amylase, papain and saccharifying enzyme in sequence to remove starch and protein.

3. Step three: inactivate enzymes in the fermented wheat bran liquid, wash it and dry it to obtain wheat bran dietary fiber.

4. The method for preparing an emulsion-stable wheat bran dietary fiber according to claim 1, wherein: In step 1, the material-liquid ratio of wheat bran to n-hexane is 1:8-1:10 (w / v).

5. The method for preparing an emulsion-stable wheat bran dietary fiber according to claim 1, characterized in that: In the mixed suspension of yeast powder and Lactobacillus plantarum in step 1, the Lactobacillus plantarum solution is prepared by mixing Lactobacillus plantarum powder with MRS culture medium at a ratio of 1:400-1:800 (w / v) and then culturing at 37°C for 15-20 h. The ratio of yeast powder to Lactobacillus plantarum suspension in the mixed culture solution is 1:80-1:100 (w / v).

6. The method for preparing an emulsion-stable wheat bran dietary fiber according to claim 1, characterized in that: The ratio of wheat bran to mixed bacterial solution in step 1 is 1:1-1:2 (v / v).

7. The method for preparing an emulsion-stable wheat bran dietary fiber according to claim 1, characterized in that: The enzyme addition procedure in the step 2 is as follows: the ratio of 4500-5000 U / mL amylase to the fermented bran liquid is 2-4% v / v, and the reaction is carried out for 1.5-2 h at a temperature of 60-70 °C and a pH of 6.5-7.5; the ratio of 2000-2500 U / mL papain to the fermented bran liquid is 1-2% v / v, and the reaction is carried out for 1-2 h at a temperature of 40-50 °C and a pH of 6.5-7.5; the ratio of saccharifying enzyme to the fermented bran liquid is 1-2% v / v, and the reaction is carried out for 1-2 h at a temperature of 55 °C and a pH of 4.5-5.

5.

8. The method for preparing an emulsion-stable wheat bran dietary fiber according to claim 1, characterized in that: In step 3, the enzyme inactivation needs to be heated to 90-100°C and maintained for 20-40 min.

9. The method for preparing an emulsion-stable wheat bran dietary fiber according to claim 1, characterized in that: The washing in step 3 is carried out with 1:5-1:10 (v / v) 95% ethanol, acetone and sterile water in sequence.

10. The method for preparing the emulsion-stable wheat bran dietary fiber according to claim 1, characterized in that: In the step 3, the drying temperature of the wheat bran is 40-50° C., and the moisture content of the wheat bran after drying is 10-15%.

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