Ferulic acid-loaded Pickering emulsion with stable cereal non-starch polysaccharide and oat starch co-gelatinized substance and preparation method of ferulic acid-loaded Pickering emulsion

Abstract

The invention discloses a ferulic acid-loaded Pickering emulsion with stable cereal non-starch polysaccharide and oat starch co-gelatinization product and a preparation method thereof, and the preparation method comprises the following steps: adding cereal non-starch polysaccharide with the molecular weight of 80-100 kDa into water, then adding oat starch into the water, gelatinizing the mixture, filtering, washing and drying to obtain the ferulic acid-loaded Pickering emulsion with stable cereal non-starch polysaccharide and oat starch co-gelatinization product. The cereal non-starch polysaccharide-oat starch co-gelatinized substance is obtained; the preparation method comprises the following steps: adding cereal non-starch polysaccharide-oat starch co-gelatinization into water to prepare a water phase, putting ferulic acid into vegetable oil to prepare an oil phase, and uniformly mixing the oil phase and the water phase to obtain a crude emulsion; the method has the characteristics of simple process, environmental protection, continuous industrial production and the like; the cereal-sourced non-starch polysaccharide has a remarkable improvement effect on physicochemical and digestion characteristics of oat starch, and can be widely applied to the field of food industry.

Description

Technical Field

[0001] The invention belongs to the field of deep processing of natural products and modern functional food processing, and particularly relates to a Pickering emulsion loaded with ferulic acid stabilized by co-gelatinization of cereal non-starch polysaccharide and oat starch and a preparation method thereof. Background Art

[0002] Natural starch is widely used in the food industry as a food thickener, fat substitute, stabilizer, and gelling agent. However, the utilization of natural starch is often limited due to some undesirable properties, such as syneresis, degradation, pH sensitivity, and thermal instability. In order to eliminate or reduce these undesirable properties, natural starch can be modified using different modification methods, one of which is the addition of non-starch polysaccharides (NSPs). This method is a relatively simple and low-cost technology that can replace chemical modification or other expensive physical modifications. Many previous studies have reported that the addition of NSPs to starch suspensions can improve viscosity, gelling properties, water binding capacity, emulsion stabilization, and prevent recrystallization, film formation, and enhance foam stabilization. These starch-NSPs complexes can be used in a variety of foods, such as ketchup, mayonnaise, salad dressing, fat simulants, and ice cream.

[0003] Oats are one of the important cultivars widely grown and consumed in northern China. It has high nutritional and medicinal value and is recognized as a low or medium glycemic index food. Starch is usually located in the oat endosperm, surrounded by β-glucan and a layer of protein-rich bran, accounting for 50%-65%. Compared with other common cereal starches, oat starch has outstanding structural characteristics and unique functional properties, including film-forming ability, foaming ability, emulsification ability and water binding ability. However, the application of native oat starch is still usually accompanied by some problems, such as low heat resistance, paste transparency, shear resistance and increased paste viscosity. In order to overcome these shortcomings, physical and chemical modifications have been introduced. For example, high hydrostatic pressure (above 400mpa) treatment destroys the crystallization of oat starch and reduces the recrystallization rate of oat starch. Subcritical ethanol-water treatment can improve the cold water expansion properties of oat starch. The present invention is intended to develop cereal non-starch polysaccharides to promote the development of functional raw materials. Summary of the invention

[0004] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0005] Another object of the present invention is to provide a Pickering emulsion stably loaded with ferulic acid from a co-gelatinized product of cereal non-starch polysaccharides and oat starch and a preparation method thereof, which has the advantages of a simple and convenient preparation method, a safe and controllable process, and can realize continuous and low-cost green production.

[0006] To this end, the technical solution provided by the present invention is: A method for preparing a Pickering emulsion loaded with ferulic acid stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch, comprising the following steps: 1) Prepare cereal non-starch polysaccharides and select components with a molecular weight of 80-100 kDa; 2) Cereal non-starch polysaccharides with a molecular weight of 80-100 kDa are added to water, and then oat starch is added thereto, the solid-liquid ratio of cereal non-starch polysaccharides is 1:350-500, and the solid-liquid ratio of oat starch is 1:50-150, and then the mixture is dispersed at a temperature of 15-30°C for 15-30 min, and then heated at 90-100°C for 15-30 min and kept stirring for gelatinization, and finally dried to obtain a cereal non-starch polysaccharide-oat starch co-gelatinization product; specifically, the mixture is dispersed at 15-30°C by magnetic stirring for 15-30 min, and then heated at 90-100°C for 15-30 min and kept stirring to ensure complete gelatinization. After cooling to room temperature, the cereal non-starch polysaccharide and corn starch co-gelatinization product is freeze-dried, and the whole cereal non-starch polysaccharide-oat starch co-gelatinization product is collected.

[0007] 3) Cereal non-starch polysaccharide-oat starch co-gelatinization product is added to water to prepare an aqueous phase, ferulic acid is placed in vegetable oil to prepare an oil phase, and the oil phase and the aqueous phase are mixed to obtain a Pickering crude emulsion loaded with ferulic acid.

[0008] Preferably, in the method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization of cereal non-starch polysaccharide and oat starch, the cereal non-starch polysaccharide-oat starch co-gelatinization is added to water to prepare a 1.5% w / w solution, and the solution is swollen at 25°C for a period of time, such as 6 hours, and stirred evenly to prepare the aqueous phase, and then ultrasonically modified so that the gelatinization degree of the cereal non-starch polysaccharide-oat starch co-gelatinization reaches more than 90%; wherein the conditions for the ultrasonic modification are: temperature not higher than 4°C, ultrasonic power 600 W, 0.5s on, 0.5s off, 20~24 kHz, 42~46 kHz, 66~70 kHz three-frequency ultrasound is performed simultaneously, and the ultrasound time is 5~10min.

[0009] Preferably, in the method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization product of cereal non-starch polysaccharide and oat starch, in step 1), the method for preparing the cereal non-starch polysaccharide comprises: The grains were ground into powder, defatted and dried, and the dried grain powder was soaked in water at a solid-liquid ratio of 20 to 45 mL / g, and then extracted using a CW-2000A-ultrasonic microwave digestion and extraction instrument, wherein the preset microwave power was 500 to 900 W, the temperature was 25 to 40°C, the processing time was 10 to 35 min, the pH value was 6 to 11, the microwave frequency was 2450 MHz, and the ultrasonic frequency was 40 KHz. Subsequently, the obtained product was leached at 60 to 90°C for 1 to 3 h, and the sample was separated to obtain the supernatant, and the supernatant was concentrated to 1 / 4 of the initial volume using a vacuum rotary evaporator, and 3 times the volume of 95% ethanol was added, and the mixture was allowed to stand overnight at 4°C, and the alcohol precipitate was centrifuged to collect the precipitate; The precipitate was dissolved in deionized water to prepare a uniform polysaccharide solution, and then transferred to an ultrafiltration device, an ultrafiltration membrane with a molecular weight cutoff of 100 kDa was selected, a peristaltic pump was turned on, a flow rate of 150-200 mL / min and a pressure of 0.2-0.3 MPa were set, and the polysaccharide solution passed through the 100 kDa ultrafiltration membrane, and the permeate was collected. Then, an ultrafiltration membrane with a molecular weight cutoff of 80 kDa was selected, a peristaltic pump was turned on, a flow rate of 80-100 mL / min and a pressure of 0.3-0.4 MPa were set, and the permeate passed through the 80 kDa ultrafiltration membrane. When the solution volume was concentrated to 1 / 10 of the original volume, the ultrafiltration was stopped, and the retentate was collected to obtain a preliminarily purified cereal non-starch polysaccharide solution; The preliminarily purified cereal non-starch polysaccharide solution is dialyzed and then freeze-dried to obtain the cereal non-starch polysaccharide.

[0010] Preferably, in the method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization of cereal non-starch polysaccharides and oat starch, in step 2), the mixture is heated at 90-100°C for 15-30 min and stirred until it is completely gelled, then cooled to room temperature, and then dried, and the drying is carried out by freeze-drying.

[0011] Preferably, in the method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization of cereal non-starch polysaccharides and oat starch, in step 3), the mass ratio of the water phase to the oil phase is 5-10:95-90.

[0012] Preferably, in the preparation method of the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization of cereal non-starch polysaccharides and oat starch, in step 3), the crude Pickering emulsion loaded with ferulic acid is then homogenized for 8 min at a temperature of 4°C, a power of 750W, 1s on, 1s off, and an amplitude of 60%, to obtain a Pickering emulsion loaded with ferulic acid. Specifically, the oil phase and the water phase are mixed at a mass ratio of 5-10: 95-90, and stirred at 8000 rpm for 1 min and 11000 rpm for 1 min using an IKA T25 digital high-speed mixer to prepare a crude emulsion. Further, a SONICS VCX750 ultrasonic cell disruptor is used in a jacketed beaker at 4°C, with a power of 750W, 1s on, 1s off, and an amplitude of 60%, and the homogenization is continued for 8 min, and the emulsion sample is stored in a brown vial at low temperature.

[0013] Preferably, in the preparation method of the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization of cereal non-starch polysaccharides and oat starch, in step 3), the method for preparing the oil phase is: dissolving ferulic acid in ethanol to a concentration of 30-60 mg / mL, then adding 30-60 mg / mL of ferulic acid ethanol solution to the vegetable oil at a volume ratio of 1-4: 9-6, and then heating and evaporating to remove ethanol to prepare the oil phase, and the vegetable oil is walnut oil. For example, ferulic acid (30-60 mg / mL) is dissolved in ethanol, stirred at 25°C for 2h to ensure that it is completely dissolved, added to walnut oil at a volume ratio of 1-4: 9-6, and stirred at 85°C for 30 min to evaporate ethanol to prepare the oil phase.

[0014] Preferably, in the preparation method of the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization of cereal non-starch polysaccharide and oat starch, in step 1), the cereal is ground into powder and then passed through a 50-mesh sieve to obtain the sieve underflow, and the sieve underflow is defatted twice with petroleum ether. The solid-liquid ratio is 1:10 for each defatting, and the defatting time is 3 hours. Then, the precipitate is centrifuged and dried.

[0015] Preferably, in the method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization product of cereal non-starch polysaccharide and oat starch, the cereal is at least one of oats, oat germ rice, black rice, purple rice, fragrant rice, millet, red rice or coix seed.

[0016] A Pickering emulsion loaded with ferulic acid stabilized by a co-gelatinization product of cereal non-starch polysaccharide and oat starch is prepared by any of the methods described above.

[0017] The present invention has at least the following beneficial effects: The present invention discloses a Pickering emulsion loaded with ferulic acid stably prepared from a co-gelatinized product of cereal non-starch polysaccharide and oat starch and a preparation method thereof, comprising: extracting non-starch polysaccharides from cereals by ultrasonic microwave assistance and hot water extraction, and obtaining cereal non-starch polysaccharides by alcohol precipitation; obtaining co-gelatinization of cereal non-starch polysaccharides and oat starch by heating co-gelatinization treatment, thereby achieving the modification effect on oat starch. Ferulic acid is dissolved in walnut oil as the oil phase, and the co-gelatinized product solution of non-starch polysaccharide and oat starch is the aqueous phase. A homogenization treatment is performed based on a high-speed mixer and an ultrasonic cell disruptor to obtain a Pickering emulsion loaded with ferulic acid stably prepared from a co-gelatinized product of cereal non-starch polysaccharide and oat starch, which can be used as food, beverage, cosmetics, or a substrate for fermentation or chemical modification. The present invention has the characteristics of simple process, green environmental protection, and continuous industrial production; cereal-derived non-starch polysaccharides have a significant improvement effect on the physicochemical and digestive properties of oat starch, and can be widely used in the field of food industry.

[0018] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a comparison chart of the swelling power of each group of polysaccharides and oat starch co-gelatinizers in the present invention.

[0020] Figure 2 This is a comparison chart of the solubility of each group of polysaccharides and oat starch co-gelatinizers in the present invention.

[0021] Figure 3 This is a comparison chart of the leached amylose content of each group of polysaccharide and oat starch co-gelatinizers in the present invention.

[0022] Figure 4 This is a comparison chart of the digestibility of the co-gelatinized products of polysaccharides and oat starch in each group of the present invention.

[0023] Figure 5 This is a diagram of ferulic acid encapsulation efficiency of the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinizer of each group of polysaccharide and oat starch in the present invention.

[0024] Figure 6 This is a graph showing the release efficiency of ferulic acid in the Pickering emulsions loaded with ferulic acid stabilized by co-gelatinization of polysaccharides and oat starch in each group of the present invention in simulated in vitro digestion. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0026] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0027] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0028] Non-starch components (NSCs) originally present in cereals, including proteins, lipids, and β-glucans, have a great influence on the digestibility of oat starch. Cereals, such as rice, purple rice, black rice, and coix seeds, are widely cultivated crops, and the non-starch polysaccharides they contain are important carbohydrate components, but they have not been fully developed and applied. In addition, ferulic acid is a hydrogenated cinnamic acid with strong antioxidant, anti-inflammatory, anti-cancer, and antiviral properties. It is also used as a candidate drug for the treatment of diseases such as diabetes, cancer, Alzheimer's disease, skin diseases, and cardiovascular diseases. It has been approved by the US Food and Drug Administration and is used as a preservative to prevent the auto-oxidation of oils. However, it is susceptible to photodegradation and degrades when exposed to oxygen. Therefore, in order to extend the shelf life and improve the release rate and utilization of ferulic acid in digestion, the use of cereal non-starch polysaccharides with oat starch stabilized Pickering emulsions as delivery vehicles for ferulic acid may be a good area of ​​research. So far, there are few reports on the effects of cereal-based NSPs on the structure and physicochemical properties of oat starch, and the development and application of Pickering emulsions stabilized by cereal non-starch polysaccharides and oat starch. Based on the above technical defects, the present invention provides a method for co-gelatinizing cereal-based polysaccharides with oat starch that has good swelling power and solubility and can help slow digestion, which is of great significance to promoting the development of functional raw materials.

[0029] In order to enable those skilled in the art to better understand the technical solution of the present invention, the following further description is now provided: Example 1 The dried fragrant rice was ground into powder using a laboratory mill and sieved through a 50-mesh screen. It was defatted twice with petroleum ether at room temperature for 3 h, with a solid-liquid ratio of 1:10 in each step. The mixture was centrifuged at 3000 × g for 15 min (H-2050R, Xiangyi, China) and then dried in a fume hood for 48 h. After drying, the powder was soaked in distilled water with a solid-liquid ratio of 1:25. It was then extracted using a CW-2000A-ultrasonic microwave digestion and extraction instrument with preset microwave power (800 W), temperature (40°C), treatment time (30 min) and pH 6.0, with a microwave frequency of 2450 MHz and an ultrasonic frequency of 40 KHz. Subsequently, the above-mentioned obtained was placed in a constant temperature water bath and extracted at 80°C for 2 h. The sample was centrifuged at 8500 rpm for 10 min to obtain the supernatant and precipitate. The supernatant was taken and concentrated to 1 / 4 of the initial volume using a vacuum rotary evaporator (60°C), 4 times the volume of 95% ethanol was added, and the mixture was allowed to stand overnight at 4°C. The alcohol precipitate was centrifuged at 8500 rpm for 10 min to collect the precipitate. The precipitate was dissolved in deionized water to prepare a uniform polysaccharide solution, which was transferred to an ultrafiltration device. An ultrafiltration membrane with a molecular weight cutoff of 100 kDa was selected, the peristaltic pump was turned on, the flow rate was set to 1750 mL / min, and the pressure was 0.25 MPa. The polysaccharide solution passed through the 100 kDa ultrafiltration membrane, and the permeate was collected. Then, an ultrafiltration membrane with a molecular weight cutoff of 80 kDa was selected, the peristaltic pump was turned on, the flow rate was set to 90 mL / min, and the pressure was 0.35 MPa. The permeate passed through the 80 kDa ultrafiltration membrane. When the solution volume was concentrated to 1 / 10 of the original volume, the ultrafiltration was stopped, and the retentate was collected to obtain a preliminarily purified cereal non-starch polysaccharide solution; The initially purified cereal non-starch polysaccharide solution was dialyzed and then freeze-dried (-60°C) to obtain the fragrant rice non-starch polysaccharide.

[0030] The fragrant rice non-starch polysaccharide was dissolved in distilled water, and then oat starch was added to each solution, with a solid-liquid ratio of 1:350 for fragrant rice non-starch polysaccharide and a solid-liquid ratio of 1:50 for oat starch. The mixture was dispersed at 25°C by magnetic stirring for 30 minutes, and then heated at 90°C for 30 minutes with continuous stirring to ensure complete gelation. After cooling to room temperature, the co-gelatinized product of fragrant rice non-starch polysaccharide and oat starch was freeze-dried and collected to obtain the co-gelatinized product of fragrant rice non-starch polysaccharide-oat starch.

[0031] Ferulic acid (50 mg / mL) was dissolved in ethanol, stirred at 25°C for 2h to ensure complete dissolution, added to walnut oil at a volume ratio of 1:9, and stirred at 85°C for 30 min to evaporate ethanol to prepare an oil phase. A 1.5% w / w solution of fragrant rice non-starch polysaccharide-oat starch co-gelatin was dissolved in ultrapure water, swelled at 25°C for 6h, stirred evenly to prepare an aqueous phase, and then ultrasonically modified, the gelatinization degree of cereal non-starch polysaccharide-oat starch co-gelatin reached 95%; wherein the conditions of the ultrasonic modification were: temperature not higher than 4°C, ultrasonic power 600 W, 0.5s on, 0.5s off, 22 kHz, 44kHz, 68 kHz three-band ultrasound at the same time, and ultrasound time of 8 min. Next, the oil phase and the water phase were mixed at a mass ratio of 5:95, and stirred at 8000 rpm for 1 min and 11000 rpm for 1 min using an IKA T25 digital high-speed mixer to prepare a crude emulsion. The emulsion was further homogenized using a SONICS VCX750 ultrasonic cell disruptor in a jacketed beaker at 4°C with a power of 750 W, 1 s on, 1 s off, and an amplitude of 60% for 8 min, and the emulsion sample was stored in a brown vial at low temperature.

[0032] Example 2 The dried millet was ground into powder using a laboratory mill and sieved through a 50-mesh screen. It was defatted twice with petroleum ether at room temperature for 3 h, with a solid-liquid ratio of 1:10 in each step. The mixture was centrifuged at 3000 × g for 15 min (H-2050R, Xiangyi, China) and then dried in a fume hood for 48 h. After drying, the powder was soaked in distilled water with a solid-liquid ratio of 1:45. It was then extracted using a CW-2000A-ultrasonic microwave digestion and extraction instrument with a preset microwave power of 900 W, temperature of 40 °C, treatment time of 30 min, and pH of 6.0. The microwave frequency was 2450 MHz and the ultrasonic frequency was 40 KHz. Subsequently, the above-mentioned obtained was placed in a constant temperature water bath and extracted at 90 °C for 2 h. The sample was centrifuged at 8500 rpm for 10 min to obtain the supernatant and precipitate. The supernatant was taken and concentrated to 1 / 4 of the initial volume using a vacuum rotary evaporator (60°C), 3 times the volume of 95% ethanol was added, and the mixture was allowed to stand overnight at 4°C. The alcohol precipitate was centrifuged at 8500 rpm for 10 min, and the precipitate was collected. The precipitate was dissolved in deionized water to prepare a uniform polysaccharide solution, which was transferred to an ultrafiltration device. An ultrafiltration membrane with a molecular weight cutoff of 100 kDa was selected, the peristaltic pump was turned on, the flow rate was set to 150 mL / min, and the pressure was 0.2 MPa. The polysaccharide solution passed through the 100 kDa ultrafiltration membrane, and the permeate was collected. Then, an ultrafiltration membrane with a molecular weight cutoff of 80 kDa was selected, the peristaltic pump was turned on, the flow rate was set to 80 mL / min, and the pressure was 0.3 MPa. The permeate passed through the 80 kDa ultrafiltration membrane. When the solution volume was concentrated to 1 / 10 of the original volume, the ultrafiltration was stopped, and the retentate was collected to obtain a preliminarily purified cereal non-starch polysaccharide solution; The preliminarily purified cereal non-starch polysaccharide solution was dialyzed and then freeze-dried (-60°C) to obtain millet non-starch polysaccharide.

[0033] Millet non-starch polysaccharides were dissolved in distilled water, and then oat starch was added to each solution, with a millet non-starch polysaccharide to liquid ratio of 1:500 and an oat starch to liquid ratio of 1:150. The mixture was dispersed at 25°C by magnetic stirring for 30 minutes, and then heated at 100°C for 30 minutes with continuous stirring to ensure complete gelation. After cooling to room temperature, the millet non-starch polysaccharide and oat starch co-gelatinization was freeze-dried and collected to obtain millet non-starch polysaccharide-oat starch co-gelatinization.

[0034] Ferulic acid (60 mg / mL) was dissolved in ethanol, stirred at 25°C for 2h to ensure complete dissolution, added to walnut oil at a volume ratio of 1:9, and stirred at 85°C for 30 min to evaporate ethanol to prepare an oil phase. Millet non-starch polysaccharide-oat starch co-gelatin was dissolved in ultrapure water to prepare a 1.5% w / w solution, swelled at 25°C for 6h, stirred evenly to prepare an aqueous phase, and then ultrasonically modified to achieve a gelatinization degree of more than 90% for the cereal non-starch polysaccharide-oat starch co-gelatin. The conditions for the ultrasonic modification were: temperature not higher than 4°C, ultrasonic power 600 W, 0.5s on, 0.5s off, 24kHz, 42 kHz, 66 kHz three-band ultrasound at the same time, and ultrasound time of 10min. Next, the oil phase and the water phase were mixed at a mass ratio of 1:9, and stirred at 8000 rpm for 1 min and 11000 rpm for 1 min using an IKA T25 digital high-speed mixer to prepare a crude emulsion. The emulsion was further homogenized using a SONICS VCX750 ultrasonic cell disruptor in a jacketed beaker at 4°C with a power of 750 W, 1 s on, 1 s off, and an amplitude of 60% for 8 min, and the emulsion sample was stored in a brown vial at low temperature.

[0035] Example 3 The dried purple rice was ground into powder using a laboratory mill and sieved through a 50-mesh screen. It was defatted twice with petroleum ether at room temperature for 3 h, with a solid-liquid ratio of 1:10 in each step. The mixture was centrifuged at 3000 × g for 15 min (H-2050R, Xiangyi, China) and then dried in a fume hood for 48 h. After drying, the powder was soaked in distilled water with a solid-liquid ratio of 1:30. It was then extracted using a CW-2000A-ultrasonic microwave digestion and extraction instrument with a preset microwave power of 900 W, temperature of 40 °C, treatment time of 30 min, and pH of 6.0. The microwave frequency was 2450 MHz and the ultrasonic frequency was 40 KHz. Subsequently, the above-mentioned obtained was placed in a constant temperature water bath and extracted at 80 °C for 2 h. The sample was centrifuged at 8500 rpm for 10 min to obtain the supernatant and precipitate. The supernatant was taken and concentrated to 1 / 4 of the initial volume using a vacuum rotary evaporator (60°C), 3 times the volume of 95% ethanol was added, and the mixture was allowed to stand overnight at 4°C. The alcohol precipitate was centrifuged at 8500 rpm for 10 min, and the precipitate was collected. The precipitate was dissolved in deionized water to prepare a uniform polysaccharide solution, which was transferred to an ultrafiltration device. An ultrafiltration membrane with a molecular weight cutoff of 100 kDa was selected, the peristaltic pump was turned on, the flow rate was set to 200 mL / min, and the pressure was 0.3 MPa. The polysaccharide solution passed through the 100 kDa ultrafiltration membrane, and the permeate was collected. Then, an ultrafiltration membrane with a molecular weight cutoff of 80 kDa was selected, the peristaltic pump was turned on, the flow rate was set to 100 mL / min, and the pressure was 0.4 MPa. The permeate passed through the 80 kDa ultrafiltration membrane. When the solution volume was concentrated to 1 / 10 of the original volume, the ultrafiltration was stopped, and the retentate was collected to obtain a preliminarily purified cereal non-starch polysaccharide solution; The preliminarily purified cereal non-starch polysaccharide solution was dialyzed and then freeze-dried (-60°C) to obtain purple rice non-starch polysaccharide.

[0036] Purple rice non-starch polysaccharide was dissolved in distilled water, and then oat starch was added to each solution, with a solid-liquid ratio of 1:400 for purple rice non-starch polysaccharide and 1:100 for oat starch. The mixture was dispersed at 25°C by magnetic stirring for 30 minutes, and then heated at 100°C for 30 minutes with continuous stirring to ensure complete gelation. After cooling to room temperature, the purple rice non-starch polysaccharide and oat starch co-gelatinization was freeze-dried and collected to obtain the purple rice non-starch polysaccharide-oat starch co-gelatinization.

[0037] Ferulic acid (30 mg / mL) was dissolved in ethanol, stirred at 25°C for 2h to ensure complete dissolution, added to walnut oil at a volume ratio of 1:4, and stirred at 85°C for 30 min to evaporate ethanol to prepare an oil phase. Millet non-starch polysaccharide-oat starch co-gelatin was dissolved in ultrapure water to prepare a 1.5% w / w solution, swelled at 25°C for 6h, stirred evenly to prepare an aqueous phase, and then ultrasonically modified to make the gelatinization degree of cereal non-starch polysaccharide-oat starch co-gelatin reach more than 90%. The conditions of the ultrasonic modification were: temperature not higher than 4°C, ultrasonic power 600 W, 0.5s on, 0.5s off, 20kHz, 46 kHz, 70 kHz three-band ultrasound at the same time, and ultrasound time of 5 min. Next, the oil phase and the water phase were mixed at a mass ratio of 1:9, and stirred at 8000 rpm for 1 min and 11000 rpm for 1 min using an IKA T25 digital high-speed mixer to prepare a crude emulsion. The emulsion was further homogenized using a SONICS VCX750 ultrasonic cell disruptor in a jacketed beaker at 4°C with a power of 750 W, 1 s on, 1 s off, and an amplitude of 60% for 8 min, and the emulsion sample was stored in a brown vial at low temperature.

[0038] Example 4 A method for preparing a ferulic acid-loaded Pickering emulsion stabilized by co-gelatinization of cereal non-starch polysaccharide and oat starch, the steps are the same as those in Example 1, except that the cereal non-starch polysaccharide is black rice polysaccharide.

[0039] Example 5 A method for preparing a Pickering emulsion loaded with ferulic acid stabilized by co-gelatinization of cereal non-starch polysaccharide and oat starch, the steps are the same as those in Example 1, except that the cereal non-starch polysaccharide is red rice polysaccharide.

[0040] Example 6 A method for preparing a Pickering emulsion loaded with ferulic acid stabilized by co-gelatinization of cereal non-starch polysaccharide and oat starch, the steps are the same as those in Example 1, except that the cereal non-starch polysaccharide is coix seed polysaccharide.

[0041] Example 7 A method for preparing a ferulic acid-loaded Pickering emulsion stabilized by co-gelatinization of cereal non-starch polysaccharide and oat starch, the steps are the same as those in Example 1, except that the cereal non-starch polysaccharide is oat germ rice polysaccharide.

[0042] Comparative Example 1 A method for preparing a Pickering emulsion loaded with ferulic acid stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch, the steps are the same as those in Example 1, except that oat starch is used alone for gelatinization treatment.

[0043] Comparative Example 2 A method for preparing a Pickering emulsion loaded with ferulic acid that is stabilized by a co-gelatinization product of cereal non-starch polysaccharides and oat starch, wherein the steps are the same as those of Example 1, except that only fragrant rice polysaccharide is used as an emulsifier to prepare the Pickering emulsion loaded with ferulic acid.

[0044] Comparative Example 3 A method for preparing a ferulic acid-loaded Pickering emulsion stabilized by co-gelatinization of cereal non-starch polysaccharide and oat starch, the steps are the same as those in Example 1, except that the cereal non-starch polysaccharide and oat starch are directly mixed without gelatinization treatment.

[0045] Comparative Example 4 A method for preparing a Pickering emulsion loaded with ferulic acid stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch, the steps are the same as those in Example 1, except that the mushroom non-starch polysaccharide is lentinan.

[0046] Comparative Example 5 A method for preparing a ferulic acid-loaded Pickering emulsion stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch, the steps are the same as those in Example 1, except that the cereal non-starch polysaccharide extraction is not assisted by ultrasound-microwave method.

[0047] Comparative Example 6 A method for preparing a ferulic acid-loaded Pickering emulsion stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch, the steps are the same as those in Example 1, except that the cereal non-starch polysaccharide extraction ultrasound uses a preset microwave power of 400 W, a temperature of 60° C., a processing time of 40 min, and a pH value of 4.0, and the solid-liquid ratio of cereal flour to water is 1:10.

[0048] Comparative Example 7 A method for preparing a ferulic acid-loaded Pickering emulsion stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch, the steps are the same as those in Example 1, except that during the co-gelatinization treatment, the cereal non-starch polysaccharide and oat starch are heated at 80° C. for 40 min and continuously stirred.

[0049] Comparative Example 8 A method for preparing a Pickering emulsion loaded with ferulic acid stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch, the steps are the same as those in Example 1, except that the Pickering emulsion loaded with ferulic acid is formed by processing with a SCIENTZ-150 high-pressure homogenizer at 600 bar.

[0050] Determination of swelling power and solubility of co-gelatinized products of cereal non-starch polysaccharides and oat starch 2% sample (w / w) was soaked in 30 mL deionized water and placed in a weighing tube. After constant heating at 95°C for 30 min, the suspension was centrifuged for 20 min (3000×g), the supernatant was collected, and the precipitate was weighed. The supernatant was dried in an oven at 105°C to constant weight. The swelling force and solubility were calculated using the following equations.

[0051] Swelling power and solubility can characterize the water absorption capacity of starch granules and the extent of amylose leaching during swelling. Figure 1 and Figure 2 The effects of polysaccharide types, polysaccharide extraction methods, and co-gelatinization methods on the swelling power and solubility of co-gelatinized products of cereal non-starch polysaccharides and oat starch are shown respectively. Compared with oat starch alone (Comparative Example 1) and non-gelatinization treatment (Comparative Example 3), the co-gelatinization treatment with the addition of cereal non-starch polysaccharides has a significant modification effect on oat starch. Compared with mushroom non-starch polysaccharides (Comparative Example 4), the swelling power and solubility of the co-gelatinized products of cereal non-starch polysaccharides and oat starch are significantly better than those of the co-gelatinized products of mushroom non-starch polysaccharides and oat starch, indicating that the co-gelatinization treatment of cereal non-starch polysaccharides and oat starch presents a better modification effect. In addition, the cereal non-starch polysaccharides obtained by ultrasonic microwave assisted extraction have a better effect of enhancing the swelling power and solubility of the co-gelatinized products than the cereal non-starch polysaccharides that have not been extracted by ultrasonic microwave assisted extraction (Comparative Example 5). This may be closely related to the fact that ultrasonic microwave assisted extraction can affect the structure and physicochemical properties of polysaccharides, and different ultrasonic microwave treatment conditions (Comparative Example 6) have different effects on the properties of polysaccharides. It is worth noting that gelatinization temperature is also an important factor affecting the properties of co-gelatinization products of cereal non-starch polysaccharides and oat starch (Comparative Example 7). Higher temperatures can make the modification effect of cereal non-starch polysaccharides on oat starch better, thereby making their co-gelatinization products have higher swelling power and solubility.

[0052] Determination of amylose extraction from co-gelatinized products of cereal non-starch polysaccharides and oat starch The content of amylose leached in the sample was measured by iodine colorimetry. The freeze-dried sample (10 mg) was weighed in a centrifuge tube, 1.0 mL of 0.2 M NaOH solution was added to extract the amylose, incubated in a 95°C water bath for 30 min, then stained with I2-KI solution and measured at 620 nm. Potato amylose was used as the standard, and the calibration curve equation (A 620 =0.9315 C + 0.0133, R 2 = 0.9987, where C is the concentration of amylose). The absorbance value of 0.2 M NaOH solution at 620 nm was used as blank.

[0053] OD sam is the absorbance value of the sample, OD ctrl is the absorbance value of the blank; V is the volume of the extract (mL); W is the weight of the sample (g).

[0054] The two main components of starch are amylose and amylopectin, which differ significantly in their properties and functions. Amylose has a high tendency to retrograde and produces hard gels and tough films. In contrast, amylopectin is more stable when dispersed in water and produces soft gels and weak films. During gelatinization, the starch crystal structure is destroyed, the granules continue to swell, and amylose penetrates into the aqueous phase between the granules. Figure 3 In the experiment, the content of amylose extracted from the co-gelatinization of mushroom non-starch polysaccharide (Comparative Example 4), cereal non-starch polysaccharide (Comparative Examples 3, 5-7, Examples 1-7) and oat starch was significantly higher than that of the oat starch gelatinization alone (Comparative Example 1). By comparison, it was found that the modification effect of cereal non-starch polysaccharide on oat starch without ultrasonic microwave assisted treatment was not significant, and the ultrasonic microwave assisted treatment conditions and co-gelatinization temperature would affect the modification effect of cereal non-starch polysaccharide on oat starch.

[0055] Determination of digestibility of co-gelatinized products of cereal non-starch polysaccharides and oat starch The sample (200 mg) was suspended in 15 mL of 0.2 M sodium acetate buffer (pH 5.2) in a 50 mL centrifuge tube. Then, a mixed enzyme (5 mL) of porcine pancreatic α-amylase (300 U / mL) and amyloglucosidase (20 U / mL) was added to the starch suspension. The mixture was incubated at 37 °C and stirred at 200 rpm in a water bath. Equal amounts (100 μL) of the hydrolyzate were extracted at 0, 20, and 120 min and immediately mixed with 900 μL of anhydrous ethanol to inactivate the enzyme. After centrifugation for 3 min, the glucose released from the sample was measured using a glucose oxidase kit (oxidase-peroxidase kit, Rongsheng Biotechnology Co., Ltd., Shanghai, China). The contents of rapidly digestible starch (RDS, hydrolyzed after 20 min), slowly digestible starch (SDS, hydrolyzed after another 100 min), and resistant starch (RS, not hydrolyzed after 120 min) were calculated by the following equations: Where TS is the weight of total starch content (mg). 20 , G 120Respectively represent the glucose content in chyme after 0, 20, and 120 min. The ratio of digested starch to glucose is 0.9.

[0056] The digestion characteristics comparison diagram of the polysaccharide and oat starch co-gelatinized products of each group of the present invention is shown in Figure 4 . Compared with the single oat starch gelatin (Comparative Example 1), the RDS content of Examples 1-7 dropped sharply from 55.95% of OS to 46.82%, 47.39%, 45.81%, 49.03%, 47.65%, 49.32% and 48.72%, respectively. On the contrary, the RS level increased. It is worth noting that there is no significant difference between the SDS content of Comparative Examples 4 and 6 and that of Comparative Example 1, and the SDS of Comparative Examples 3, 5 and 7 show a certain increasing trend. Therefore, cereal non-starch polysaccharides have a significant inhibitory effect on the digestion of oat starch and may help blood sugar control. In vitro digestion systems usually contain enzymes, starch and non-starch components (NSCs). The interactions between these chemicals may all affect the digestion of starch. The inhibition of digestion by non-starch components (NSCs) may be attributed to several reasons. The first is that NSCs can form physical barriers such as membranes around starch molecules, thereby reducing the affinity between digestive enzymes and substrates and reducing the accessibility of enzymes. Second, the molecular entanglement and overlap induced by NSCs and starch, as well as the self-assembly behavior of NSCs in water, significantly increased the viscosity of the reaction mixture, thereby limiting the mobility of water and reducing the release and diffusion of starch hydrolysis products (including glucose). Third, the molecular adsorption between NSCs and hydrolytic enzymes may promote the reduction of starch digestion rate due to its non-competitive inhibition reaction. Finally, the microstructural strengthening of the composite gel may be due to the interaction between biomacromolecules, resulting in a decrease in starch digestion with the increase of NSPs addition.

[0057] Determination of encapsulation efficiency of ferulic acid in Pickering emulsions loaded with ferulic acid stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch The samples were demulsified using methanol to recover the encapsulated ferulic acid. Briefly, 1 mL of methanol was added to 200 μL of sample, vortexed for 2 min and centrifuged at 8500 rpm for 10 min. To determine the ferulic acid content in the Pickering emulsion samples, 800 μL of supernatant was added to 200 μL of methanol, kept on a magnetic stirrer at 250 rpm for 6 h, centrifuged again at 8500 rpm for 10 min, and the supernatant was collected and its absorbance was measured at 321 nm by spectrophotometry to determine the ferulic acid encapsulation efficiency.

[0058] Among them, FA 释放 is the ferulic acid content released from Pickering emulsion particles, FA添加 is the initial amount of ferulic acid added.

[0059] The digestion characteristics comparison diagram of each group of polysaccharides and oat starch co-gelatinized products of the present invention is shown in Figure 5 . Compared with Comparative Example 4, it can be seen that the Pickering emulsion stabilized by the co-gelatinization of cereal non-starch polysaccharides and oat starch has significantly better ferulic acid encapsulation efficiency than the Pickering emulsion stabilized by the co-gelatinization of lentinan and oat starch. In addition, the non-gelatinization treatment and gelatinization treatment conditions affect the emulsification properties of the co-gelatinization of cereal non-starch polysaccharides and oat starch, and then affect the stability of its Pickering emulsion. Compared with the ultrasonic treatment (Examples 1-7), the Pickering stability prepared based on the high-pressure homogenization treatment method (Comparative Example 8) is not as good as the Pickering stability of the ultrasonic dispersion homogenization treatment. In addition, the cereal non-starch polysaccharides that have not been extracted and treated with ultrasonic microwave assistance (Comparative Example 5) are not conducive to enhancing the emulsification stability of the co-gelatinization of cereal non-starch polysaccharides and oat starch.

[0060] Determination of ferulic acid release rate from ferulic acid-loaded Pickering emulsions stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch during in vitro digestion To 10 mg of sample, 10 mL of phosphate buffer solution (PBS, pH 7.2) containing α-amylase was added. The reaction mixture was incubated at 37°C in a shaking water bath for 5 min, followed by centrifugation at 5500 rpm for 10 min, and the absorbance of the supernatant was recorded at 321 nm. The recovered sample was treated with 10 mL of simulated gastric fluid (3 g / L pepsin, 8.5 g / L sterile NaCl solution, 1.0 mol / L HCl to adjust the pH to 1.6), the reaction mixture was incubated at 37°C, centrifuged at 5500 rpm for 10 min, and the absorbance of the supernatant was recorded at 321 nm after a time interval of 60 min to determine the ferulic acid content released after simulated gastric conditions (SGD). In the next stage, the particles were treated with 10 mL of simulated intestinal fluid (3 g / L bile salts, 10 g / L pancreatin dissolved in phosphate buffer solution, pH 7.5) and the absorbance was recorded at 321 nm after 120 min of digestion to determine the amount of ferulic acid released after simulated intestinal digestion (SID).

[0061] The digestion characteristics comparison diagram of each group of polysaccharides and oat starch co-gelatinized products of the present invention is shown in Figure 6. Compared with oat non-starch polysaccharide alone (Comparative Example 1), or cereal non-starch polysaccharide alone (Comparative Example 2), and the complex of cereal non-starch polysaccharide and oat starch that has not been gelatinized (Comparative Example 3), the Pickering emulsion based on the co-gelatinization of cereal non-starch polysaccharide and oat starch stably loaded with ferulic acid can better achieve the circumvention effect in gastrointestinal digestion and increase the release and absorption of ferulic acid in the intestine (Examples 1-7). It is worth noting that the gelatinization treatment method (Comparative Examples 3, 7) has a significantly stronger effect on the sustained release effect of the co-gelatinization of cereal non-starch polysaccharide and oat starch in in vitro digestion than other treatment methods (Comparative Examples 1-2, 4-6).

[0062] Although the embodiments of the present invention are disclosed above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the embodiments of the present invention. For those familiar with the art, other modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and equivalent scopes, the embodiments of the present invention are not limited to the specific details and the legends shown and described here.

Claims

1. A method for preparing a Pickering emulsion loaded with ferulic acid stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch, characterized in that: The steps include: 1) Prepare cereal non-starch polysaccharides and select components with a molecular weight of 80-100 kDa; 2) adding a cereal non-starch polysaccharide with a molecular weight of 80-100 kDa to water, and then adding oat starch thereto, the solid-liquid ratio of the cereal non-starch polysaccharide is 1:350-500, and the solid-liquid ratio of the oat starch is 1:50-150, and then dispersing the mixture at a temperature of 15-30°C for 15-30 min, and then heating at 90-100°C for 15-30 min and stirring for gelatinization, and finally freeze-drying to obtain a cereal non-starch polysaccharide-oat starch co-gelatinized product; 3) Cereal non-starch polysaccharide-oat starch co-gelatinization product is added to water to prepare an aqueous phase, ferulic acid is placed in vegetable oil to prepare an oil phase, and the oil phase and the aqueous phase are mixed to obtain a Pickering crude emulsion loaded with ferulic acid.

2. The method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization product of cereal non-starch polysaccharide and oat starch according to claim 1, characterized in that: In step 3), the cereal non-starch polysaccharide-oat starch co-gelatinized product is added to water to prepare a 1.5% w / w solution, and the solution is swollen at 25°C for a period of time, stirred evenly to prepare the aqueous phase, and then ultrasonically modified to make the gelatinization degree of the cereal non-starch polysaccharide-oat starch co-gelatinized product reach more than 90%; wherein the conditions for the ultrasonic modification are: temperature not higher than 4°C, ultrasonic power 600 W, 0.5s on, 0.5s off, 20~24 kHz, 42~46 kHz, 66~70 kHz three-frequency ultrasound simultaneously, and the ultrasound time is 5~10 min.

3. The method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization product of cereal non-starch polysaccharide and oat starch according to claim 1, characterized in that: In step 1), the method for preparing cereal non-starch polysaccharides comprises: The grains were ground into powder, defatted and dried, and the dried grain powder was soaked in water at a solid-liquid ratio of 20-45 mL / g, and then extracted using an ultrasonic microwave digestion extractor, wherein the microwave power was 500-900 W, the temperature was 25-40°C, the processing time was 10-35 min, the pH value was 6-11, the microwave frequency was 2450 MHz, and the ultrasonic frequency was 40 KHz. Subsequently, the obtained product was leached at 60-90°C for 1-3 h, and the sample was separated to obtain the supernatant, and the supernatant was concentrated to 1 / 4 of the initial volume using a vacuum rotary evaporator, and 3 times the volume of 95% ethanol was added, and the mixture was allowed to stand at 4°C overnight, and the alcohol precipitate was centrifuged to collect the precipitate; The precipitate was dissolved in deionized water to prepare a uniform polysaccharide solution, and then transferred to an ultrafiltration device, an ultrafiltration membrane with a molecular weight cutoff of 100 kDa was selected, a peristaltic pump was turned on, a flow rate of 150-200 mL / min and a pressure of 0.2-0.3 MPa were set, and the polysaccharide solution passed through the 100 kDa ultrafiltration membrane, and the permeate was collected. Then, an ultrafiltration membrane with a molecular weight cutoff of 80 kDa was selected, a peristaltic pump was turned on, a flow rate of 80-100 mL / min and a pressure of 0.3-0.4 MPa were set, and the permeate passed through the 80 kDa ultrafiltration membrane. When the solution volume was concentrated to 1 / 10 of the original volume, the ultrafiltration was stopped, and the retentate was collected to obtain a preliminarily purified cereal non-starch polysaccharide solution; The preliminarily purified cereal non-starch polysaccharide solution is dialyzed and then freeze-dried to obtain the cereal non-starch polysaccharide.

4. The method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization product of cereal non-starch polysaccharide and oat starch according to claim 1, characterized in that: In step 2), the mixture is heated at 90-100° C. for 15-30 min and stirred until it is completely gelled, then cooled to room temperature, and then dried, wherein the drying is performed by freeze drying.

5. The method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization product of cereal non-starch polysaccharide and oat starch according to claim 1, characterized in that: In step 3), the mass ratio of the water phase to the oil phase is 5-10:95-90.

6. The method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization product of cereal non-starch polysaccharide and oat starch according to claim 1, characterized in that: In step 3), the Pickering crude emulsion loaded with ferulic acid is then homogenized for 8 min at a temperature of 4° C., a power of 750 W, 1 s on, 1 s off, and an amplitude of 60% to obtain a Pickering emulsion loaded with ferulic acid.

7. The method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization product of cereal non-starch polysaccharide and oat starch according to claim 1, characterized in that: In step 3), the method for preparing the oil phase is: dissolving ferulic acid in ethanol to make its concentration 30-60 mg / mL, then adding 30-60 mg / mL of ferulic acid ethanol solution to the vegetable oil in a volume ratio of 1-4:9-6, and then heating and evaporating to remove ethanol to prepare the oil phase, wherein the vegetable oil is walnut oil.

8. The method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization product of cereal non-starch polysaccharide and oat starch according to claim 2, characterized in that: In step 1), the grains are ground into powder and then passed through a 50-mesh sieve to obtain the sieve residue, which is then defatted twice with petroleum ether; the solid-liquid ratio is 1:10 for each defatting, and the defatting time is 3 hours. The precipitate is then centrifuged and dried.

9. The method for preparing the Pickering emulsion loaded with ferulic acid stabilized by the co-gelatinization product of cereal non-starch polysaccharide and oat starch according to claim 1, characterized in that: The cereal is at least one of oats, oat germ rice, black rice, purple rice, fragrant rice, millet, red rice or coix seed.

10. A Pickering emulsion loaded with ferulic acid stabilized by co-gelatinization of cereal non-starch polysaccharides and oat starch, characterized in that: It is prepared by the method according to any one of claims 1 to 9.

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