Cereal bran polysaccharide, its preparation method and application as emulsifier

Abstract

The application provides a cereal bran polysaccharide, a preparation method thereof and application thereof as an emulsifier, and belongs to the technical field of polysaccharide extraction. The preparation method of the cereal bran polysaccharide comprises the following steps: performing oil removal treatment on cereal bran to obtain oil-removed cereal bran; performing steam explosion treatment on the oil-removed cereal bran to obtain steam-expanded cereal bran; the steam explosion treatment is performed under the following conditions: the temperature is 160-220 DEG C, the pressure is 1.0-2.5 MPa, and the time is 10-15 min; performing starch removal treatment on the steam-expanded cereal bran to obtain a starch-removed material; performing deconstruction treatment on the starch-removed material under alkaline conditions to obtain an alkali extract solution; adjusting the pH value of the alkali extract solution to an acid condition, and then sequentially performing alcohol precipitation, dialysis and freeze drying to obtain the cereal bran polysaccharide. The cereal bran polysaccharide provided by the application has excellent emulsification stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polysaccharide extraction, and particularly relates to a cereal bran polysaccharide, a preparation method thereof and application of the cereal bran polysaccharide as an emulsifier. BACKGROUND

[0002] A large amount of cereal bran is produced in the process of deep processing of cereals, 85% of which is utilized as animal feed, agricultural fertilizer and other products with low added value. With the improvement of living standards, people pay more and more attention to health, especially dietary health, and the demand for dietary fiber supplement is also growing. Cereal bran is rich in cellulose and hemicellulose and is a high-quality natural source of dietary fiber, which has a wide development potential. One of the main components in cereal bran is hemicellulose B, namely arabinoxylan, which is an important component of plant cell walls. As a plant polysaccharide, arabinoxylan has the advantages of being natural, non-toxic, having strong biological activity and being widely available. In addition, studies have shown that arabinoxylan has certain emulsifying properties and can be used as an emulsifier in oil-in-water emulsions.

[0003] Arabinoxylan is covalently connected to other components such as lignin and cellulose through lactone bonds at ferulic acid sites. The key to extracting arabinoxylan lies in breaking the force between these components and separating them by utilizing the characteristics of each component. The currently popular method for extracting arabinoxylan due to its high efficiency is alkali extraction. Under the condition of strong alkali and high temperature, hydroxyl ions cause cellulose to swell, break the hydrogen bonds between cellulose and arabinoxylan and the ester bonds between phenolic acids, thereby efficiently releasing arabinoxylan. However, the emulsion stability of arabinoxylan prepared by alkali extraction still needs to be improved. SUMMARY

[0004] The present application aims to provide a cereal bran polysaccharide, a preparation method thereof and application of the cereal bran polysaccharide as an emulsifier. The cereal bran polysaccharide provided by the present application has excellent emulsion stability.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The present application provides a preparation method of a cereal bran polysaccharide, comprising the following steps:

[0007] The cereal bran is subjected to a deoiling treatment to obtain deoiled cereal bran;

[0008] The deoiled cereal bran is subjected to a steam explosion treatment to obtain steam-expanded cereal bran; the conditions of the steam explosion treatment include a temperature of 160-220 DEG C, a pressure of 1.0-2.5 MPa and a time of 10-15 min;

[0009] The steam-expanded grain bran is subjected to destarch treatment to obtain destarched material;

[0010] The destarched material was subjected to deconstruction treatment under alkaline conditions to obtain an alkaline extract solution; the deconstruction treatment was carried out under ultrasonic conditions.

[0011] The pH of the alkaline extract solution was adjusted to acidic conditions, and then subjected to alcohol precipitation, dialysis, and freeze-drying in sequence to obtain the cereal bran polysaccharide.

[0012] Preferably, the grain bran includes one or more of corn bran, sorghum bran, and wheat bran; the degreasing agent used in the degreasing treatment includes one or more of n-hexane, petroleum ether, and ethanol; the mass ratio of the grain bran to the degreasing agent is 1:5~10; the temperature of the degreasing treatment is 15~35℃, and the time is 0.5~1.5h.

[0013] Preferably, the mass ratio of the deoiled grain bran to the water used in the steam explosion treatment is 1:2~8.

[0014] Preferably, the destarch removal process includes: mixing the steam-expanded grain bran with water for gelatinization, and mixing the resulting gelatinized liquid with amylase for enzymatic hydrolysis to obtain destarched material.

[0015] Preferably, the mass ratio of the steam-expanded grain bran to the water used for gelatinization is 1:5~9; the temperature of the gelatinization treatment is 80~100℃, and the time is 0.5~1.5h.

[0016] Preferably, the amylase is a thermostable α-amylase; the enzymatic hydrolysis treatment is performed at a temperature of 65~90℃ for a time of 0.5~2h.

[0017] Preferably, the alkaline condition is pH=10~12.5; the number of deconstruction treatments is 2~3 times; the conditions for each deconstruction treatment independently include: temperature of 80~90℃, time of 0.5~2h, ultrasonic power of 200~2000W, ultrasonic frequency of 10~50kHz, and sound wave amplitude of 30~60%.

[0018] Preferably, the acidic conditions are pH=3~5; the alcohol precipitation reagent used is ethanol, and the mass ratio of the alcohol precipitation reagent to the solution to be precipitated is 2~5:1; the dialysate used for dialysis is water; and the molecular weight cutoff of the dialysis bag used for dialysis is 3.5~14kDa.

[0019] This invention provides cereal bran polysaccharide prepared by the preparation method described in the above technical solution.

[0020] This invention provides the application of the cereal bran polysaccharide described above as an emulsifier in oil-in-water emulsions.

[0021] This invention provides a method for preparing cereal bran polysaccharides, comprising the following steps: degreasing cereal bran to obtain deoiled cereal bran; subjecting the deoiled cereal bran to steam explosion treatment to obtain steam-expanded cereal bran; the steam explosion treatment conditions include: temperature of 160~220℃, pressure of 1.0~2.5MPa, and time of 10~15min; destarching the steam-expanded cereal bran to obtain destarched material; destructuring the destarched material under alkaline conditions to obtain an alkaline extract solution; adjusting the pH of the alkaline extract solution to acidic conditions, followed by sequential alcohol precipitation, dialysis, and freeze-drying to obtain the cereal bran polysaccharide. This invention utilizes steam explosion treatment combined with ultrasound-assisted alkaline extraction. This synergistic process optimizes the structure and functional properties of arabinoxylan through physical, chemical, and mechanical actions, thereby enhancing its emulsifying properties. Specifically, this invention utilizes steam explosion to significantly disrupt the cell wall structure of grain bran, releasing arabinoxylan and partially depolymerizing it, reducing its molecular weight, optimizing its molecular structure, and exposing phenolic groups such as ferulic acid, thereby enhancing its binding ability to the oil-water interface and improving its emulsifying properties. This invention also utilizes ultrasound assistance to promote the penetration of alkaline solution into the raw material, and the resulting shear force further reduces the molecular weight of arabinoxylan, making it easier to disperse in water and achieving more effective emulsion stabilization. In addition, this invention removes impurities such as starch through enzymatic hydrolysis and purifies the grain bran polysaccharide through alcohol precipitation and dialysis, reducing impurities and ultimately obtaining a grain bran polysaccharide with excellent emulsifying stability, providing a theoretical basis for the further high-value utilization of grain bran. Detailed Implementation

[0022] This invention provides a method for preparing cereal bran polysaccharide, comprising the following steps:

[0023] The grain bran is deoiled to obtain deoiled grain bran;

[0024] The deoiled grain bran is subjected to steam explosion treatment to obtain steam-expanded grain bran; the conditions for the steam explosion treatment include: temperature of 160~220℃, pressure of 1.0~2.5MPa, and time of 10~15min.

[0025] The steam-expanded grain bran is subjected to destarch treatment to obtain destarched material;

[0026] The destarched material was subjected to deconstruction treatment under alkaline conditions to obtain an alkaline extract solution; the deconstruction treatment was carried out under ultrasonic conditions.

[0027] The pH of the alkaline extract solution was adjusted to acidic conditions, and then subjected to alcohol precipitation, dialysis, and freeze-drying in sequence to obtain the cereal bran polysaccharide.

[0028] This invention employs a combination of steam explosion treatment and ultrasound-assisted alkaline extraction (i.e., deconstruction treatment), which significantly improves the yield of cereal bran polysaccharides while optimizing their molecular weight distribution, ultimately yielding cereal bran polysaccharides with excellent emulsifying properties. Specifically, during the steam explosion treatment, the high-temperature and high-pressure environment disrupts the structure of the cereal bran cell walls, releasing more arabinoxylan and effectively reducing the interference of lignin and cellulose on the subsequent deconstruction treatment process. Furthermore, the steam explosion treatment enhances the swelling effect of cellulose, creating more favorable conditions for subsequent deconstruction treatment. The ultrasound-assisted alkaline extraction method utilizes cavitation and shearing effects to promote the release of arabinoxylan and improve its emulsifying properties. Compared to single alkali extraction, the arabinoxylan obtained by steam explosion treatment combined with ultrasound-assisted alkali extraction in this invention exhibits superior rheological properties when dissolved in water, enabling it to better stabilize emulsions. When used in oil-in-water emulsions, it can adsorb onto the surface of oil droplets and form a thicker hydrophilic interfacial layer around them. Compared to protein-based emulsifiers, the cereal bran polysaccharide described in this invention exhibits higher stability under complex environmental conditions such as pH, ionic strength, and temperature variations. The preparation method of the cereal bran polysaccharide described in this invention is described in detail below.

[0029] Unless otherwise specified, all raw materials used in this invention are commercially available products well known to those skilled in the art.

[0030] This invention involves degreasing grain bran to obtain deoiled grain bran. In one embodiment, the grain bran may include one or more of corn bran, sorghum bran, and wheat bran, specifically corn bran, sorghum bran, or wheat bran. In another embodiment, the grain bran is preferably crushed and sieved before degreasing, using an 80-mesh sieve, and the undersize material is collected for the degreasing process. In another embodiment, the degreasing agent used may include one or more of n-hexane, petroleum ether, and ethanol, specifically n-hexane; the mass ratio of grain bran to the degreasing agent can be 1:5~10, more preferably 1:7~8; the degreasing temperature can be 15~35℃, specifically room temperature; and the degreasing time can be 0.5~1.5h, specifically 1h. In another embodiment, after degreasing, the resulting system is preferably filtered to remove the organic solvent, yielding the deoiled grain bran. In this embodiment of the invention, the degreasing process performed under the above conditions can remove the oil from the grain bran, which helps to avoid storage and purity problems caused by the presence of oil.

[0031] After obtaining deoiled grain bran, the present invention subjectes the deoiled grain bran to steam explosion treatment to obtain steam-expanded grain bran. In one embodiment of the present invention, the deoiled grain bran is mixed with water and subjected to steam explosion treatment; the mass ratio of the deoiled grain bran to the water used in the steam explosion treatment can be 1:2~8, specifically 1:2.5, 1:3, 1:4, or 1:5. In the present invention, the conditions for the steam explosion treatment include: a temperature of 160~220℃, specifically 170, 180, or 190℃; a pressure of 1.0~2.5MPa, specifically 1.5MPa or 2.0MPa; and a time of 10~15min, specifically 10min, 11min, 12min, 13min, 14min, or 15min. In another embodiment of the present invention, after the steam explosion treatment, it is preferable to reduce the pressure and cool to ambient temperature and pressure, and then centrifuge the resulting system to remove the supernatant to obtain the steam-expanded grain bran. In this embodiment of the invention, steam explosion treatment under the above conditions can effectively destroy the cell wall structure and promote the release of active ingredients, ultimately yielding cereal bran polysaccharide with excellent emulsification stability.

[0032] After obtaining steam-expanded grain bran, the present invention performs a destarch treatment on the steam-expanded grain bran to obtain a destarched material. As one embodiment of the present invention, the destarch treatment may include: mixing the steam-expanded grain bran with water for gelatinization, and mixing the resulting gelatinized solution with amylase for enzymatic hydrolysis to obtain the destarched material.

[0033] In one embodiment of the present invention, the mass ratio of the steam-expanded grain bran to the water used for gelatinization can be 1:5~9, specifically 1:6 or 1:7; the gelatinization temperature can be 80~100℃, specifically 90℃ or 95℃; and the gelatinization time can be 0.5~1.5h, specifically 1h. The present invention, through gelatinization, can disrupt the crystal structure of starch, making it easier for enzymes to hydrolyze or dissolve, thereby improving starch removal efficiency and preventing the contamination of starch and other sugar impurities in the final product, ultimately yielding grain bran polysaccharides with excellent emulsification stability.

[0034] In one embodiment of the present invention, the amylase can be a thermoresistant α-amylase; based on 100g of steam-expanded grain bran, the activity of the thermoresistant α-amylase can be 6.5×10⁻⁶. 4 ~7×10 4 U. In one embodiment of the present invention, the temperature of the enzymatic hydrolysis treatment can be 65~90℃, more specifically 80~85℃; the time of the enzymatic hydrolysis treatment can be 0.5~2h, specifically 50min; the enzymatic hydrolysis treatment can be carried out under stirring conditions. In this embodiment of the present invention, specifically, the system obtained after gelatinization is cooled to the temperature of the enzymatic hydrolysis treatment, and then amylase is added for enzymatic hydrolysis treatment. In another embodiment of the present invention, after the enzymatic hydrolysis treatment, the obtained system is preferably heated to boiling to inactivate the enzyme, and then the obtained system is washed with water to obtain the destarched material; the water used for washing can be deionized water, and the number of washings can be 3~5 times. In this embodiment of the present invention, the destarch treatment under the above conditions can prevent starch from encapsulating arabinoxylan and preventing its release, and reduce the interference of impurities on the final product, which is beneficial to improving the extraction efficiency and purity of the final product, and finally obtaining cereal bran polysaccharide with excellent emulsification stability.

[0035] After obtaining the destarched material, the present invention deconstructs the material under alkaline conditions to obtain an alkaline extract solution; the deconstruction treatment is carried out under ultrasonic conditions. In one embodiment of the present invention, the destarched material is mixed with water, and the pH of the system is adjusted to alkaline conditions for deconstruction treatment. In another embodiment of the present invention, the mass ratio of the destarched material to water can be 1:5~10, specifically 1:7 or 1:8; the alkaline conditions can be pH=10~12.5, further specifically 10.5~11.5; the reagent used to adjust the pH value can be a sodium hydroxide solution, and the concentration of the sodium hydroxide solution can be 40~60wt%, specifically 50wt%. In one embodiment of the present invention, the deconstruction treatment can be performed 2 to 3 times; the conditions for each deconstruction treatment are independent, including: temperature of 80 to 90°C, specifically 85°C; time of 0.5 to 2 hours, specifically 1 hour; ultrasonic power of 200 to 2000W, specifically 800W or 1000W; ultrasonic frequency of 10 to 50kHz, specifically 25kHz or 30kHz; and acoustic amplitude of 30 to 60%, specifically 40% or 50%. After completing one deconstruction treatment, the present invention preferably centrifuges the resulting system, collects the supernatant and precipitate separately, and performs the precipitate for the next deconstruction treatment and centrifugation. Finally, the supernatants obtained from each centrifugation are combined as an alkaline extract solution. In one embodiment of the present invention, the conditions for each centrifugation include: temperature of 15 to 35°C, specifically room temperature; rotation speed of 7000 to 9000 r / min, specifically 8000 r / min; and time of 40 to 60 minutes, specifically 50 minutes. In this embodiment of the invention, ultrasonic-assisted deconstruction processing is performed under the above conditions, which can fully dissociate hemicellulose from the grain bran, while improving extraction efficiency and optimizing the polysaccharide structure, ultimately yielding grain bran polysaccharide with excellent emulsification stability.

[0036] After obtaining the alkaline extract solution, the pH value of the alkaline extract solution is adjusted to acidic conditions, followed by alcohol precipitation, dialysis, and freeze-drying to obtain the cereal bran polysaccharide. In one embodiment of the invention, the acidic conditions can be pH 3-5, more specifically 4-4.5; the reagent used to adjust the pH value of the alkaline extract solution can be concentrated hydrochloric acid, with a concentration of 12 mol / L. In another embodiment of the invention, after adjusting the pH value of the alkaline extract solution to acidic conditions, a solid precipitates in the system. After centrifugation, the supernatant (i.e., the solution containing cereal bran polysaccharide) is collected and sequentially washed and dialyzed to obtain the cereal bran polysaccharide. In another embodiment of the invention, the centrifugation conditions include: a temperature of 15-35°C, specifically room temperature; a rotation speed of 7000-9000 r / min, specifically 8000 r / min; and a time of 40-60 min, specifically 50 min. In one embodiment of the present invention, the alcohol precipitation reagent used can be ethanol, specifically anhydrous ethanol; the mass ratio of the alcohol precipitation reagent to the solution to be precipitated (i.e., a solution containing cereal bran polysaccharides) can be 2-5:1, specifically 3:1; the alcohol precipitation temperature can be 4-25℃, more specifically 4-8℃; the time can be 10-15 hours, specifically 12 hours. In another embodiment of the present invention, after alcohol precipitation, the supernatant is preferably removed, the precipitate is collected, washed with ethanol, reconstituted with water, and then dialysis is performed; the water can be ultrapure water; the dialysis fluid used for dialysis can be water, specifically distilled water; the molecular weight cutoff of the dialysis bag used for dialysis can be 3.5-14 kDa, more specifically 5-8 kDa; the dialysis time can be 24-72 hours, more specifically 36-48 hours. In the embodiments of the present invention, alcohol precipitation and dialysis under the above conditions are beneficial for removing low-molecular-weight impurities (such as small-molecule sugars and ash), ultimately yielding cereal bran polysaccharides with good emulsification stability. The present invention does not impose any special limitations on the freeze-drying conditions; conditions well known to those skilled in the art can be used.

[0037] This invention provides a cereal bran polysaccharide prepared by the method described in the above technical solution. The cereal bran polysaccharide provided by this invention exhibits excellent emulsifying properties as an emulsifier. When used in oil-in-water emulsions, it can adsorb onto the surface of oil droplets and form a thick hydrophilic interfacial layer around the droplets. Compared to protein-based emulsifiers, the cereal bran polysaccharide used as an emulsifier shows higher stability under conditions of pH, ionic strength, and temperature changes. Specifically, the cereal bran polysaccharide of this invention is cereal bran arabinoxylan.

[0038] This invention provides the application of the grain bran polysaccharide described above as an emulsifier in oil-in-water emulsions. As one embodiment of this invention, the grain bran polysaccharide can be used as a food-grade emulsifier in beverages, dairy products, cosmetics, and other fields.

[0039] This invention primarily utilizes steam explosion treatment combined with ultrasound-assisted alkaline extraction to prepare cereal bran polysaccharides, which exhibit characteristics such as low impurities, high extraction rate, and good emulsifying properties. Furthermore, this invention also investigated the stability of the oil-in-water emulsion prepared using the aforementioned cereal bran polysaccharides under different environmental conditions (mainly pH, ionic strength, and temperature), demonstrating that the cereal bran polysaccharides possess excellent emulsifying properties.

[0040] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] Example 1

[0042] The grain bran (specifically corn bran) was crushed using a pulverizer and passed through an 80-mesh sieve. The sieve material was collected to obtain grain bran powder. The grain bran powder was mixed with n-hexane at a mass ratio of 1:7 and deoiled at room temperature for 1 hour. The resulting system was then filtered to remove the organic solvent, yielding deoiled grain bran.

[0043] The deoiled grain bran was mixed with deionized water at a mass ratio of 1:3, and steam explosion was performed at a temperature of 180°C and a pressure of 2MPa for 10 minutes. After depressurization and cooling, the resulting system was centrifuged to remove the supernatant, and steam-expanded grain bran was obtained.

[0044] The steam-expanded grain bran was mixed with deionized water at a mass ratio of 1:7, heated to boiling, and gelatinized for 1 hour. Then, the mixture was cooled to 85°C, and a heat-resistant α-amylase (with an activity of 6.5 × 10⁻⁶ per 100g of steam-expanded grain bran) was added to the resulting gelatinized liquid. 4 U), under stirring conditions, incubate for 50 minutes for enzymatic hydrolysis (the absence of starch in the system, as determined by iodine solution detection, indicates complete enzymatic hydrolysis); after enzymatic hydrolysis, heat to boiling to inactivate the enzyme, then add deionized water to the resulting system for 5 washes to obtain destarched material;

[0045] The destarched material was mixed with deionized water at a ratio of 1:8 and heated to 85°C. During the heating process, the pH of the system was adjusted to 11.5 using NaOH solution (concentration of 50wt%). The mixture was subjected to deconstruction treatment for 1 hour under ultrasonic power of 1000W, ultrasonic frequency of 30kHz and acoustic amplitude of 50%. The resulting product system was then centrifuged at room temperature and speed of 8000r / min for 50 minutes. The supernatant and precipitate were collected separately. The precipitate was subjected to deconstruction treatment and centrifugation once more in accordance with the above steps. The supernatants were combined to obtain an alkaline extract solution.

[0046] The pH of the alkaline extract solution was adjusted to 4 using hydrochloric acid (12 mol / L). The solution was centrifuged at 8000 r / min for 50 min at room temperature, and the supernatant was collected as a solution containing cereal bran polysaccharide (arabinoxylan). This cereal bran polysaccharide solution was mixed with anhydrous ethanol at a volume ratio of 1:3 and refrigerated at 4°C for 12 h. The supernatant was then removed without stirring the precipitate. The precipitate was washed three times with anhydrous ethanol, and then reconstituted with ultrapure water. Dialysis was then performed (the dialysis bag had a molecular weight cutoff of 5 kDa, the dialysis buffer was distilled water, and the dialysis time was 48 h). After dialysis, the solution was freeze-dried to obtain cereal bran polysaccharide (specifically corn bran polysaccharide) with a purity of 80% and a yield of 15%.

[0047] Example 2

[0048] The procedure was followed as described in Example 1, except that corn bran was replaced with wheat bran, resulting in wheat bran polysaccharide with a purity of 83% and a yield of 13%.

[0049] Example 3

[0050] The procedure was followed as described in Example 1, except that corn bran was replaced with sorghum bran, resulting in sorghum bran polysaccharide with a purity of 82% and a yield of 16%.

[0051] Comparative Example 1

[0052] The procedure was carried out in accordance with the method of Example 1, except that the steam explosion treatment was omitted, that is, the deoiled grain bran was directly deconstructed, and the final grain bran polysaccharide had a purity of 50% and a yield of 8%.

[0053] Test Example 1

[0054] The emulsification stability of the cereal bran polysaccharides prepared in each embodiment and comparative example was tested under different ionic strength conditions, as detailed below:

[0055] Under stirring conditions at room temperature, cereal bran polysaccharides were added in batches to a sodium benzoate-citric acid mixed solution to obtain a well-dissolved and homogeneous emulsifier stock solution. The concentrations of sodium benzoate, citric acid, and cereal bran polysaccharides in the emulsifier stock solution were 0.1 wt%, 0.3 wt%, and 3 wt%. The emulsifier stock solution was mixed with soybean oil at a mass ratio of 9:1 and sheared for 3 minutes at 20,000 rpm using a high-speed shear mill. Then, it was homogenized three times at a homogenization pressure of 400 bar for 5 minutes each time to obtain an oil-in-water emulsion. NaCl was added to the oil-in-water emulsion to obtain NaCl concentrations of 0 mM, 50 mM, 100 mM, 200 mM, and 300 mM, respectively. The particle size was then measured using a laser particle size analyzer to test the emulsification stability of the oil-in-water emulsion under different ionic strength conditions.

[0056] The emulsification stability test results of the cereal bran polysaccharides prepared in each embodiment and the comparative example under different ionic strength conditions are shown in Table 1. It can be seen that, compared with the comparative example, the cereal bran polysaccharides prepared in the embodiments of the present invention have excellent emulsification stability under different ionic strength conditions.

[0057] Table 1. Results of emulsification stability test of cereal bran polysaccharides under different ionic strength conditions.

[0058]

[0059] Test Example 2

[0060] The emulsification stability of the cereal bran polysaccharides prepared in each embodiment and comparative example was tested under different pH conditions, as detailed below:

[0061] An oil-in-water emulsion was prepared according to the method in Test Example 1. The pH value of the oil-in-water emulsion was adjusted to 3, 6, 8 and 11 respectively using sodium hydroxide solution or hydrochloric acid. Then, the particle size was measured using a laser particle size analyzer to test the emulsification stability of the oil-in-water emulsion under different pH conditions.

[0062] The emulsification stability test results of the cereal bran polysaccharides prepared in each embodiment and the comparative example under different pH conditions are shown in Table 2. It can be seen that, compared with the comparative example, the cereal bran polysaccharides prepared in the embodiments of the present invention have excellent emulsification stability under different pH conditions.

[0063] Table 2. Results of emulsification stability test of cereal bran polysaccharides under different pH conditions.

[0064]

[0065] Test Example 3

[0066] The emulsification stability of the cereal bran polysaccharides prepared in each embodiment and comparative example was tested under different temperature conditions, as detailed below:

[0067] An oil-in-water emulsion was prepared according to the method in Test Example 1. The oil-in-water emulsion was heated at 70°C, 80°C, 90°C and 100°C for 0.5 h, respectively. Then, its particle size was measured by a laser particle size analyzer to test the emulsification stability of the oil-in-water emulsion under different temperature conditions.

[0068] The emulsification stability test results of the cereal bran polysaccharides prepared in each embodiment and the comparative example under different temperature conditions are shown in Table 3. It can be seen that, compared with the comparative example, the cereal bran polysaccharides prepared in the embodiments of the present invention have excellent emulsification stability after treatment under different temperature conditions.

[0069] Table 3. Results of emulsification stability test of cereal bran polysaccharides after treatment under different temperature conditions.

[0070]

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of a cereal bran polysaccharide as an emulsifier in an oil-in-water emulsion, wherein the preparation method of the cereal bran polysaccharide comprises the following steps: The grain bran is subjected to deoiling treatment to obtain deoiled grain bran; the deoiling reagent used in the deoiling treatment is one or more of n-hexane, petroleum ether and ethanol; the mass ratio of the grain bran to the deoiling reagent is 1:5 to 10; the deoiling treatment temperature is 15 to 35°C and the time is 0.5 to 1.5 hours. The deoiled grain bran is subjected to steam explosion treatment to obtain steam-expanded grain bran; the conditions for the steam explosion treatment include: The temperature is 160–220℃, the pressure is 1.0–2.5 MPa, and the time is 10–15 min; the mass ratio of the deoiled grain bran to the water used in the steam explosion treatment is 1:2–8. The steam-expanded grain bran is subjected to destarch treatment to obtain destarched material; The destarched material is subjected to deconstruction treatment under alkaline conditions to obtain an alkaline extract solution; the deconstruction treatment is carried out under ultrasonic conditions; the alkaline conditions are pH = 10 to 12.5; the deconstruction treatment is performed 2 to 3 times; the conditions for each deconstruction treatment are independent and include: temperature of 80 to 90°C, time of 0.5 to 2 hours, ultrasonic power of 200 to 2000 W, ultrasonic frequency of 10 to 50 kHz, and sound wave amplitude of 30 to 60%; The pH of the alkaline extract solution was adjusted to acidic conditions, and then subjected to alcohol precipitation, dialysis and freeze drying in sequence to obtain the cereal bran polysaccharide; the acidic conditions were pH = 3 to 5.

2. The application according to claim 1, characterized in that, The grain bran includes one or more of corn bran, sorghum bran, and wheat bran.

3. The application according to claim 1, characterized in that, The destarch removal process includes: mixing the steam-expanded grain bran with water for gelatinization, and mixing the resulting gelatinized liquid with amylase for enzymatic hydrolysis to obtain destarched material.

4. The application according to claim 3, characterized in that, The mass ratio of the steam-expanded grain bran to the water used in the gelatinization process is 1:5 to 9; the gelatinization process is carried out at a temperature of 80 to 100°C for a time of 0.5 to 1.5 hours.

5. The application according to claim 3 or 4, characterized in that, The amylase is a thermostable α-amylase; the enzymatic hydrolysis treatment is carried out at a temperature of 65–90°C for a time of 0.5–2 hours.

6. The application according to claim 1, characterized in that, The alcohol precipitation reagent used is ethanol, and the mass ratio of the alcohol precipitation reagent to the solution to be precipitated is 2-5:1; the dialysate used for dialysis is water; and the molecular weight cutoff of the dialysis bag used for dialysis is 3.5-14 kDa.

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