CN101798585A - Method for high-yield production of oat polysaccharide with naked oat bran as raw material - Google Patents

Abstract

The invention relates to a method for obtaining high-yield oat polysaccharides using naked oat bran as a raw material. The method uses naked oat bran as a raw material, undergoes ultrafine pulverization, ethanol pretreatment, multiple extractions with water as an extraction solvent, and combined extraction. solution, adding enzyme to degrade starch, isoelectric point deproteinization or protease hydrolysis deproteinization, vacuum concentration, ethanol precipitation, standing, suction filtration, collecting precipitates, freeze drying or hot air drying to obtain oat polysaccharides. The extraction yield of the oat polysaccharide extracted by the present invention is greater than 12g oat polysaccharide/100g naked oat bran, and the monosaccharide composition of the obtained oat polysaccharide is xylose and glucose, (1→3) glycosidic bond and (1→4) glycosidic bond The ratio is 1:1.3～1.3:1.

Description

Method for obtaining high-yield oat polysaccharides from naked oat bran

technical field

The invention belongs to the technical field of oat deep processing, in particular to a method for obtaining high-yield oat polysaccharides from naked oat bran.

Background technique

Dietary fiber (Dietary Fiber) is a natural organic polymer compound, which is a non-starch polysaccharide formed by dehydration and polymerization of monosaccharides. It cannot be decomposed by digestive enzymes in the human body, but can be degraded and utilized by microorganisms in the large intestine. An indispensable class of carbohydrates for health.

Previous studies believed that the main component of oat polysaccharides was β-glucan, and its molecular structure was a linear polysaccharide composed of D-glucose connected by β-(1,3) and β-(1,4) glycosidic bonds. The ratio of glycosidic bonds is roughly 7:3; the distribution of β-(1,3) and β-(1,4) glycosidic bonds in oat β-glucan is neither completely ordered nor completely disordered, and β- The (1,3) bond exists alone, and the β-(1,4) bond exists in 2 or 3 connections, up to 14 glucan units; Glycans, etc. are tightly bound together.

The oat polysaccharide extracted from oat bran is soluble in water, acid and dilute alkali, but insoluble in ethanol, but its solubility is affected by the particle size of oat polysaccharide, β-glucanase activity, temperature, pH and medium ions. High-purity oat polysaccharide is white, odorless and completely neutral. Its compound structure and function are relatively ideal. It does not contain gluten and phytic acid, and there are very few residues of heavy metals and pesticides. It also does not contain microorganisms. It is relatively stable and almost Not affected by temperature and pH, it has high viscosity, strong water holding capacity, good emulsification and emulsification stability, and stable fiber network.

The rheological properties are determined by the structure, molecular size and shape of β-glucan in solution. K.Autio et al. studied the rheological properties of oat β-glucan under different conditions of temperature, concentration and shear rate. The research showed that the flow curve of 0.2-1.56% β-glucan conforms to the Power-law model. Shear Thinning Pseudoplastic Fluids. Doublier and Wood research believes that oat glue containing 80% β-glucan shows irregular curling behavior in solution, and points out that viscosity and concentration are highly correlated when the concentration is higher than 0.3%. Kulicke's research shows that when the concentration is higher than the critical concentration, the viscosity and concentration show an exponential relationship. I.A.Nnann et al. compared the viscous behavior and colloidal properties of oat glue and other food colloids at different shear rates, indicating that oat β-glucan can be compounded with guar gum and other food colloids and used in the food industry.

The relative molecular mass and concentration of β-glucan will also affect the gelation property. The reduction of relative molecular mass and disaggregation of β-glucan will reduce the viscosity and increase the gel performance; β-glucan with low relative molecular mass Glycans are more likely to form gels than β-glucans with a higher molecular weight. The gelling properties of polysaccharides can be widely used in jams, puddings and other foods to affect the texture of foods.

Because oat polysaccharides are mostly combined with proteins, there are difficulties in extraction. The existing extraction methods cannot fully extract oat polysaccharides, and the yield is low.

By searching, two patent documents relevant to the present invention are found, one of which is a method (CN101558845) for comprehensively extracting oat starch, protein powder, and β-glucan from oat bran, which mainly includes the following steps: 1. Soak and refine oat bran; 2. Separation of starch from slurry; 3. Adjust pH value of liquid components to precipitate oat protein; 4. Separation of β-glucan from filtrate; 5. Separation and purification of oat starch; 6. Oat protein purification. The second is a method for extracting oat β-glucan (CN1869077), which includes the following steps: 1) stirring oat bran with water at 50-60°C to adjust the pH to 8-10; 2) adding protease at 45- Treat the protein in hydrolyzed oat bran at 60°C; 3) add α-amylase to treat at 80°C, and filter to obtain a clear liquid; 4) Filter with an ultrafiltration membrane with a molecular weight cut-off of 30000-50000Da to obtain β-glucose The polysaccharide solution was freeze-dried to obtain the β-glucan product.

Most of the above two patent documents improve the yield of oat polysaccharides, but they are essentially different from the technical solutions of this patent application.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for obtaining high-yield oat polysaccharides from naked oat bran.

The purpose of the present invention is achieved through the following technical solutions:

A method for obtaining high-yield oat polysaccharides from naked oat bran, the steps of which are:

(1) Ultrafine pulverization pretreatment: the naked oat bran is superfinely pulverized, so that the fineness of the naked oat bran reaches more than 200 mesh;

(2) Ethanol pretreatment: Add 50%-80% (V/V) ethanol aqueous solution through the naked oat bran of superfine treatment, the material-liquid ratio is 1: (3-4) (g/v), at 60 Incubate at -80°C for 10-40min, discard the supernatant, and repeat the previous operation 2-3 times for the insoluble matter in the lower layer;

(3) Water extraction: the ratio of water to naked oat bran raw materials is (6-10): 1 (mL: g), incubate at 70-90°C for 80-120min, filter, collect filtrate, repeat the above operation for insoluble matter 2 times, the combined filtrates were concentrated in vacuo to one-third of the original volume;

(4) Starch removal process: add 3000-6000U of heat-resistant amylase per 1000L of filtrate, heat to above 95°C for 10-30min, cool to 60°C, add 3000-6000U of glycosidase, and keep for 10-30min;

(5) Deproteinization by isoelectric point: adjust the pH value of the extract to 4.5, let it stand at 0-30°C for 2-4h, centrifuge or filter, collect the supernatant or filtrate, and adjust the pH of the solution to 6.0- 7.0, vacuum concentrated to 1/2 of the original volume;

(6) Vacuum concentration: vacuum <0.1MPa, concentrate the extract to more than 10% at 45-65°C;

(7) Ethanol precipitation: Slowly add ethanol to the feed liquid under stirring conditions, so that the ethanol concentration is greater than 70%, stand at 0-30°C for 6-24h, filter or centrifuge, collect solid matter, and then get naked oat bran High-yield oat polysaccharides were obtained from bark as raw material.

Moreover, the isoelectric point in the step (5) is used to remove protein by protease hydrolysis instead of protein, that is, add 10000U to 400000U of protease per 1000L filtrate, keep it at 50-60°C for 20-40min, and concentrate in vacuo to the original half of the volume.

Advantage and positive effect of the present invention are:

The present invention uses naked oat bran as a raw material, undergoes ultrafine pulverization treatment and ethanol pretreatment in sequence, and then extracts oat polysaccharides, and the extraction yield of oat polysaccharides obtained by this technology is greater than 12g oat polysaccharides/100g naked oat bran The monosaccharide composition of the obtained oat polysaccharide is xylose and glucose, and the ratio of (1→3) glycosidic bond to (1→4) glycosidic bond is 1:1.3-1.3:1.

Detailed ways

Below in conjunction with the examples, the present invention is further described, the following examples are illustrative, not limiting, and the protection scope of the present invention cannot be limited by the following examples.

Specific embodiments of the invention:

1. Weigh 1000kg of naked oat bran, and use an ultrafine pulverizer to pulverize it to make it finer than 200 mesh.

2. Add 50%-80% (V/V) ethanol aqueous solution to the above-mentioned processed naked oat bran, and the ratio of material to liquid is 1: (3-4) (g naked oat bran/v ethanol solution). Incubate at 60-80°C for 10-40min, discard the supernatant, and repeat the previous operation 2-3 times for the insoluble matter in the lower layer.

3. Ethanol-treated naked oat bran, volatilize to remove ethanol, add distilled water, the material/liquid ratio is (6-10): 1 (mL distilled water: g naked oat bran), keep warm at 70°C-90°C for 80min- After 120 min, filter and collect the filtrate, repeat the above operation twice for insoluble matter, combine the filtrates, and concentrate in vacuo to one-third of the original volume.

4. Add 10000-60000U of heat-resistant amylase to the filtrate, heat to above 95°C, keep warm for 10-30min, cool to 60°C, add 10000-60000U of glycosidase, and keep for 10-30min.

5. Adjust the pH of the extract to 4.5, let stand at 0-30°C for 2-4 hours, centrifuge or filter, collect the supernatant or filtrate, adjust the pH of the solution to 7.0, and concentrate in vacuum to 1/2 of the original volume; Or add 60,000-4,000,000 U of protease to the extract, keep it at 50-60°C for 20-40min, and concentrate it in vacuum to 1/2 of the original volume.

6. Vacuum degree <0.1MPa, concentrate the extract to more than 10% at 45-65°C;

7. Under vigorous stirring, slowly add ethanol to the extract concentrate to make the concentration of ethanol greater than 70%, and let it stand at 0-30°C for 6-24h, filter or centrifuge, collect solid matter, freeze-dry or hot-air dry , to obtain oat polysaccharides.

Through analysis, the extraction yield of oat polysaccharide obtained by this technology is greater than 12g oat polysaccharide/100g naked oat bran, and the monosaccharide composition of the obtained oat polysaccharide is xylose and glucose, (1→3) glycosidic bond and (1→4 ) The ratio of glycosidic bonds is 1:1.3-1.3:1.

Claims (2)

1. one kind is the method that raw material obtains high yield oat polysaccharide with the naked oats wheat bran, and it is characterized in that: step is:

(1) micronizing pre-treatment: the naked oats wheat bran reaches more than 200 orders fineness of naked oats wheat bran through micronizing;

(2) ethanol pre-treatment: the naked oats wheat bran of handling through ultra micro adds the aqueous ethanolic solution of 50%-80% (V/V), and the feed liquid ratio is 1: (3-4) (g/v), in 60-80 ℃ of insulation 10-40min, abandoning supernatant, lower floor's insolubles repeats last time and operates 2-3 time;

(3) water extraction: the ratio of water and naked oats wheat bran raw material is (6-10): 1 (mL: g), in 70-90 ℃ of insulation 80-120min, filter, collect filtrate, insolubles repeats aforesaid operations 2 times, merging filtrate, and vacuum concentration is to 1/3rd of original volume;

(4) starch removing process: every 1000L filtrate adds the heat-resisting amylase of 3000-6000U, is heated to more than 95 ℃ to keep 10-30min, is cooled to 60 ℃, adds Glycosylase 3000-6000U, keeps 10-30min;

(5) iso-electric point removes protein: the pH value of extracting solution is adjusted to 4.5, leaves standstill 2-4h in 0-30 ℃, and centrifugal or filter, collect supernatant liquor or filtrate, the pH that regulates this solution is 6.0-7.0, vacuum concentration is to 1/2nd of original volume;

(6) vacuum concentration: vacuum tightness＜0.1MPa is concentrated to extracting solution more than 10% under 45-65 ℃;

(7) ethanol sedimentation: add down slowly ethanol in feed liquid in agitation condition, make alcohol concn greater than 70%, leave standstill 6-24h in 0-30 ℃, filter or centrifugation, collect solid matter, promptly being able to the naked oats wheat bran is that raw material obtains high yield oat polysaccharide.

2. according to claim 1 is the method that raw material obtains high yield oat polysaccharide with the naked oats wheat bran, it is characterized in that: the iso-electric point in the described step (5) removes protein and adopts the protease hydrolysis method to remove protein to substitute, be the proteolytic enzyme that every 1000L filtrate adds 10000U～400000U, in 50-60 ℃ of maintenance 20-40min, vacuum concentration is to 1/2nd of original volume.