Composite nanoparticle-stabilized capsaicin Pickering emulsion and preparation method thereof

Abstract

The invention provides a capsaicin Pickering emulsion with stable composite nanoparticles and a preparation method of the capsaicin Pickering emulsion, and belongs to the field of preparation of Pickering emulsions. According to the method, whey protein and carboxylated nanocellulose are subjected to vortex homogenization to obtain composite nanoparticles, the Pickering emulsion is prepared through ultrasonic homogenization, and capsaicin is successfully loaded in the emulsion. The capsaicin-loaded whey protein composite cellulose Pickering emulsion has a relatively high protection effect on capsaicin, in addition, the prepared Pickering emulsion can be degraded in intestinal tracts, a large amount of capsaicin is released in the intestinal tracts, and the biological utilization efficiency of the capsaicin is improved.

Description

Technical Field

[0001] The invention relates to the field of Pickering emulsion preparation, and in particular to a composite nanoparticle-stabilized capsaicin Pickering emulsion and a preparation method thereof. Background Art

[0002] Capsaicin is the main bioactive ingredient in peppers, with multiple effects such as antibacterial, anti-inflammatory, promoting fat metabolism, and analgesia. However, the molecular structure of capsaicin contains a long hydrophobic alkyl chain and a polar vanillylamide group. The hydrophobic alkyl chain makes the capsaicin molecule highly hydrophobic. At the microscopic level, when capsaicin is in an aqueous solution environment, the hydrophobic alkyl chains will aggregate with each other to reduce the contact area with water molecules, resulting in extremely poor solubility of capsaicin in water. They tend to form aggregates, which makes capsaicin extremely unstable in aqueous solution. As a result, in the body, capsaicin is difficult to disperse evenly in body fluids, thus affecting its effective contact with biological targets. When passing through the biological membrane, although the hydrophobicity of capsaicin helps it interact with the lipid bilayer of the biological membrane, the presence of aggregates hinders its diffusion into the cell in the form of a monomer, resulting in low bioavailability, which greatly limits its wide application in various fields. Therefore, the development of an effective carrier system to improve the stability, solubility and bioavailability of capsaicin has become a research hotspot.

[0003] The stability of Pickering emulsions relies on the unique adsorption behavior of solid particles at the oil-water interface. Unlike traditional emulsions that rely on surfactant molecules to form monolayers or multilayers at the oil-water interface, the solid particles in Pickering emulsions are usually at the nanometer to micrometer level. These particles have a certain surface roughness and surface energy, and can spontaneously adsorb to the oil-water interface. When solid particles contact the oil-water interface, part of the particles will be embedded in the oil phase, and the other part will remain in the water phase. Because the surface of the particles has certain hydrophilic and lipophilic regions, a "wedge"-like structure is formed at the oil-water interface, which is tightly arranged at the interface to prevent the aggregation of oil droplets. From an energy perspective, the adsorption of solid particles at the oil-water interface reduces the interfacial free energy of the entire system, making the emulsion system more stable. This stability is manifested in the microscopic form of a solid particle interface film formed around the oil droplets. This film can effectively resist the damage to the oil droplets by external mechanical forces, temperature changes and other factors. Under high temperature conditions, due to the interactions between particles (such as electrostatic effects, hydrogen bonds, etc.), the interfacial film can still remain intact, preventing the fusion of oil droplets, thereby maintaining the chemical stability of the Pickering emulsion. In the in vivo environment, if the solid particles used in the Pickering emulsion are biocompatible materials, such as protein particles, polysaccharide particles, etc., their interactions with biological molecules and cells are relatively mild. This is because the chemical groups and physical properties on the surface of these particles have certain similarities with biological systems and will not cause strong immune responses or cytotoxicity, reflecting their good biocompatibility. At present, Pickering emulsions show great potential in the food, pharmaceutical, cosmetics and other industries.

[0004] Common organic solid particles include starch particles such as corn starch, which can be loaded with antibiotics, vitamins, etc., and have the advantages of low cost and good biocompatibility, but poor mechanical strength; protein particles such as soy protein can be loaded with hormones, antioxidants, etc., and have good emulsification and stability, but are sensitive to pH and temperature; cellulose such as microcrystalline cellulose can be loaded with drugs and probiotics, etc., and have advantages such as high mechanical strength and degradability, but also have shortcomings such as difficulty in processing. They all have unique physical and chemical properties and play different roles after forming Pickering emulsions. According to the application scope of Pickering emulsions and the requirements of the preparation process for solid particles in the emulsion, the ideal solid particles should have the following characteristics: non-toxic, safe, edible, and degradable; no reaction with the active ingredients during preparation or storage; and meet the standards of food additives.

[0005] Researchers have shown that the main absorption site of capsaicin is in the small intestine, but if their residence time in the human body is insufficient or due to its high pH, ​​the unabsorbed capsaicin may be degraded in the intestine. Therefore, it is necessary to improve the bioavailability of capsaicin in the intestinal environment.

[0006] Whey protein has good surface activity and can effectively reduce the oil-water interfacial tension; carboxylated cellulose, as a solid stabilizer, can be adsorbed on the oil-water interface to form a physical barrier to prevent droplet aggregation. The combination of the two has a good synergistic emulsification effect, can form a more stable interfacial film, and improve the physical stability of the emulsion. There is currently no report on the use of whey protein and carboxylated cellulose to prepare Pickering emulsions. Summary of the invention

[0007] The purpose of the present invention is to provide a composite nanoparticle-stabilized capsaicin Pickering emulsion and a preparation method thereof. The method uses two solid particles, whey protein and carboxylated nanocellulose, to encapsulate a capsaicin solution to prepare an emulsion, so as to improve its stability and enhance the sustained-release effect in the intestine.

[0008] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0009] The present invention provides a method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion, comprising:

[0010] Step 1: Dispersing whey protein and carboxylated nanocellulose in deionized water respectively, and then mixing and drying the two to obtain composite nanoparticles;

[0011] Step 2: adding the citric acid solution to the composite nanoparticles in step 1 to prepare a nanoparticle suspension;

[0012] Step 3: dissolving capsaicin powder in soybean oil and performing ultrasonic homogenization to obtain a capsaicin oil solution;

[0013] Step 4: then add the nanoparticle suspension of step 2 into the capsaicin oil solution of step 3, mix, and perform ice bath ultrasonic homogenization to obtain a composite nanoparticle-stabilized capsaicin Pickering emulsion.

[0014] Preferably, the mass ratio of the whey protein and the carboxylated nanocellulose in step 1 is (1-4):(1-4).

[0015] Preferably, the concentration of the citric acid solution in step 2 is 10 mmol / L.

[0016] Preferably, in step 2, citric acid is added to prepare a solution, and hydrochloric acid is used to adjust the pH value of the solution to 3.0±0.1.

[0017] Preferably, the concentration of the nanoparticle suspension in step 2 is 0.1-6%.

[0018] Preferably, the mass mg of the capsaicin powder in step three: the volume mL of the soybean oil is 1:1.

[0019] Preferably, the conditions for ultrasonic homogenization in step 3 are: power of 650 W, temperature of 20° C., and time of 30 min.

[0020] Preferably, the mixing time in step 4 is 5 minutes.

[0021] Preferably, the ice bath ultrasonic homogenization in step 4 is carried out under the conditions of: power of 650 W, ultrasonication for 2 seconds with an interval of 2 seconds, and ultrasonication time of 5-20 minutes.

[0022] The present invention also provides a capsaicin Pickering emulsion stabilized by composite nanoparticles obtained by the preparation method.

[0023] Beneficial Effects of the Invention

[0024] The present invention provides a composite nanoparticle-stabilized capsaicin Pickering emulsion and a preparation method thereof. The method uses whey protein and carboxylated nanofibers as composite particles to prepare the Pickering emulsion through ultrasonic homogenization, and successfully loads capsaicin. The Pickering emulsion formed by the composite whey protein and carboxylated nanocellulose in the present invention provides a stable microenvironment for capsaicin, significantly improves the water solubility and stability of capsaicin, and reduces its degradation loss during storage and use. The emulsion of the present invention has a high loading efficiency and encapsulation rate for capsaicin, and improves the utilization rate of capsaicin.

[0025] The Pickering emulsion prepared by the present invention can effectively prevent capsaicin from being degraded under adverse conditions such as light and high temperature, thereby extending its storage period. In addition, the Pickering emulsion prepared by the present invention will degrade in the intestine, release a large amount of capsaicin in the intestine, and improve the bioavailability of capsaicin. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The ζ-potential diagram of the capsaicin Pickering emulsion stabilized by the composite nanoparticles prepared by the present invention under conditions of different pH values ​​and different particle concentrations.

[0027] Figure 2 Optical microscope image of the capsaicin Pickering emulsion stabilized by the composite nanoparticles prepared by the present invention.

[0028] Figure 3 A graph showing the change in particle size distribution of capsaicin Pickering emulsions stabilized by composite nanoparticles of different proportions prepared in Examples 1-5 of the present invention at 25° C. for 21 days.

[0029] Figure 4Capsaicin retention rate, average particle size and ζ-potential diagram of the composite nanoparticle-stabilized capsaicin Pickering emulsion prepared in Example 1 and Comparative Examples 1-2 of the present invention under different salt ion concentration conditions.

[0030] Figure 5 Capsaicin retention rate, average particle size and ζ-potential diagram of the composite nanoparticle-stabilized capsaicin Pickering emulsion prepared in Example 1 and Comparative Examples 1-2 of the present invention under different temperature conditions.

[0031] Figure 6 Capsaicin retention rate, average particle size and ζ-potential diagram of the composite nanoparticle-stabilized capsaicin Pickering emulsion prepared in Example 1 and Comparative Examples 1-2 of the present invention under different UV lamp (18W) irradiation time conditions.

[0032] Figure 7 Cumulative release curves of capsaicin in the in vitro digestion simulations of the gastric (0-120 min) and intestinal (120-240 min) of the composite nanoparticle-stabilized capsaicin Pickering emulsion and capsaicin oil solution prepared in Example 1 and Comparative Examples 1-2 of the present invention. DETAILED DESCRIPTION

[0033] The present invention provides a method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion, comprising:

[0034] Step 1, weighing whey protein and carboxylated nanocellulose, respectively dispersed in deionized water; mixing the two dispersions and drying them to obtain composite nanoparticles, wherein the mixing temperature is preferably room temperature, the mixing time is preferably 5 minutes, the drying method is not particularly limited, preferably vacuum freeze drying, the drying time is preferably 12 hours, and the mass ratio of the whey protein to the carboxylated nanocellulose is preferably (1-4): (1-4), more preferably 1:4, 2:3, 1:1, 3:2 or 4:1, and most preferably 1:4;

[0035] Step 2: Measure deionized water, add citric acid to make a solution, adjust the pH value of the solution with hydrochloric acid, add the composite nanoparticles in step 1 to form a nanoparticle suspension; the nanoparticle content is preferably 0.1-6%, more preferably 0.1%, 0.2%, 0.4%, 1%, 2%, 3%, 4%, 5%, 6% (g: mL), and most preferably 0.2%, the concentration of the citric acid solution is preferably 10 mmol / L, the pH value of the adjusted suspension is 3.0±0.1, and 1 mol / L HCl is preferably used for adjustment;

[0036] Step 3, weighing 2.5 mg of capsaicin powder, dissolving the weighed capsaicin powder in 2.5 mL of soybean oil and performing ultrasonic homogenization to obtain a capsaicin oil solution; the mass mg of the capsaicin powder: the volume mL of the soybean oil is 1:1, and the concentration of the capsaicin solution is preferably 1 mg / mL; the ultrasonic homogenization conditions are preferably 650 W of power, 30 min of time, and 20° C.;

[0037] Step 4: Add the capsaicin solution prepared in step 3 to the nanoparticle suspension in step 2, and vortex mix; the vortex time is preferably 5 minutes; and then ultrasonic homogenization is performed to obtain a capsaicin Pickering emulsion stabilized by composite nanoparticles. The ultrasonic homogenization conditions are preferably 650W power, 2s intervals for each ultrasonic 2s, and an ultrasonic time of 5-20min, preferably 10min.

[0038] The present invention also provides a capsaicin Pickering emulsion stabilized by composite nanoparticles obtained by the preparation method.

[0039] The technical solution of the present invention is fully described below in the form of specific embodiments in conjunction with the accompanying drawings.

[0040] Example 1

[0041] Step 1, weigh 0.05 g of whey protein and carboxylated nanocellulose in a mass ratio of 1:4, and disperse them in deionized water respectively;

[0042] Step 2: Mix the two dispersions in step 1 and vortex for 5 minutes, and dry for 12 hours to obtain composite nanoparticles;

[0043] Step 3: Measure 22.5 mL of deionized water and add citric acid to prepare a 10 mmol / L citric acid solution, and adjust the pH value of the solution to 3.0±0.1 with a 1 mol / L hydrochloric acid solution, and add the composite nanoparticles prepared in step 2 to prepare a nanoparticle suspension;

[0044] Step 4, weigh 2.5 mg of capsaicin powder, dissolve the weighed capsaicin powder in 2.5 mL of soybean oil and perform ultrasound, the specific conditions of ultrasound are: power 650 W, time 30 min, temperature 20° C., to obtain a capsaicin oil solution;

[0045] Step 5: Add the capsaicin solution prepared in step 4 to the suspension in step 3, and vortex mix for 5 minutes;

[0046] Step 6: Ultrasonic homogenization was performed on the mixed suspension obtained in step 5. The specific conditions of ultrasonic homogenization were as follows: power of 650 W, ultrasonication for 2 seconds, and ultrasonication for 10 minutes to obtain a capsaicin Pickering emulsion stabilized by composite nanoparticles; optical microscope: Figure 2 as shown Figure 2 It can be seen that the emulsion droplets have a complete structure, without droplet collapse and droplet aggregation, and the droplet sizes are uniform, showing relatively anti-aggregation ability.

[0047] Example 2

[0048] The preparation method and steps are the same as those in Example 1, except that the mass ratio of carboxylated nanocellulose to whey protein is 1:4.

[0049] Example 3

[0050] The preparation method and steps are the same as those in Example 1, except that the mass ratio of carboxylated nanocellulose to whey protein is 2:3.

[0051] Example 4

[0052] The preparation method and steps are the same as those in Example 1, except that the mass ratio of carboxylated nanocellulose to whey protein is 3:3.

[0053] Example 5

[0054] The preparation method and steps are the same as those in Example 1, except that the mass ratio of carboxylated nanocellulose to whey protein is 3:2.

[0055] Effect of the particle size distribution of the composite nanoparticle-stabilized capsaicin Pickering emulsion prepared in Examples 1-5 over time: The particle size of the emulsion was measured at 25 °C under dark conditions, as Figure 3 shown. Among them Figure 3 a represents the particle size of the Pickering emulsion stabilized by composite nanoparticles with different ratios on the 1st day of preparation, Figure 3 b represents the particle size of the Pickering emulsion stabilized by composite nanoparticles with different ratios on the 21st day of preparation, Figure 3 a and Figure 3 b, the curve A represents the particle size distribution of the Pickering emulsion stabilized when the ratio of whey protein to carboxylated nanocellulose in the composite particles is 4:1, the curve B represents the particle size distribution of the Pickering emulsion stabilized when the ratio of whey protein to carboxylated nanocellulose in the composite particles is 3:2, the curve C represents the particle size distribution of the Pickering emulsion stabilized when the ratio of whey protein to carboxylated nanocellulose in the composite particles is 1:1, the curve D represents the particle size distribution of the Pickering emulsion stabilized when the ratio of whey protein to carboxylated nanocellulose in the composite particles is 2:3, and the curve E represents the particle size distribution stabilized when the ratio of whey protein to carboxylated nanocellulose in the composite particles prepared in Example 1 is 1:4. Figure 3This indicates that the Pickering emulsion with a high proportion of carboxylated nanocellulose in the composite particles has a particle size of nanometer level and presents a single narrow peak distribution. After 21 days of storage, the Pickering emulsion with a high proportion of carboxylated nanocellulose does not experience a significant increase in average particle size, and the particle size distribution only moves slightly and is very stable. Among them, the Pickering emulsion prepared in Example 1 has the most stable particle size distribution.

[0056] In order to investigate the effect of pH and nanoparticle concentration on the ζ-potential of the capsaicin Pickering emulsion, the pH and nanoparticle concentration in Example 1 were changed, and the emulsion particle size was tested at 25° C. in the dark. Figure 1 As shown. Figure 1 a represents the ζ-potential of the Pickering emulsion at different pH conditions, Figure 1 b represents the ζ-potential of the Pickering emulsion under different nanoparticle concentration conditions. Figure 1 It is shown that when the pH is 3 and the nanoparticle concentration is 0.2% (g: mL), the absolute value of the ζ-potential of the Pickering emulsion prepared in Example 1 is the highest and the emulsion stability is the strongest.

[0057] Comparative Example 1

[0058] The preparation steps and parameters were the same as those in Example 1, except that the mass ratio of whey protein to carboxylated nanofibers in step 1 was 0:5. The retention rate, average particle size of the emulsion and ζ-potential results were as follows: Figure 4-6 shown.

[0059] Comparative Example 2

[0060] The preparation steps and parameters were the same as those in Example 1, except that the mass ratio of whey protein to carboxylated nanofibers in step 1 was 5:0. The retention rate, average particle size of the emulsion and ζ-potential results were as follows: Figure 4-6 shown.

[0061] Capsaicin retention rate test: 1 mL of the Pickering emulsion prepared in Example 1, Comparative Example 1 and Comparative Example 2 was mixed with 4 mL of extraction solvent (dichloromethane / methanol = 2:1, v / v) to extract capsaicin. After centrifugation at 4500 rpm for 20 min, the dichloromethane layer was collected. This process was repeated twice, the extracts were combined, and then the absorbance was measured at 480 nm using an ELISA reader. The standard curve of capsaicin (y = 1669.7x + 36.08, R 2 =0.9997) to calculate the content of capsaicin.

[0062]

[0063] The storage stability test of the composite nanoparticle-stabilized capsaicin Pickering emulsion prepared in Example 1 and Comparative Examples 1-2 was performed. 19 portions of the emulsion prepared in Example 1, 1 mL each, were placed in NaCl concentrations of 0, 30, 50, 100, 200, 300 mmol / L and at 25, 50, 60, 70, 80, 90°C and UV light (18W) for 0, 2, 4, 6, 8, 10, 12 h to perform storage stability tests, determine the capsaicin content, calculate the retention rate of capsaicin, the average particle size of the emulsion, and the ζ-potential. The results are as follows: Figure 4-6 shown.

[0064] Figure 4 The capsaicin retention rate, average particle size and ζ-potential diagram of the composite nanoparticle-stabilized capsaicin Pickering emulsion prepared in Example 1 and Comparative Examples 1-2 under different NaCl concentration conditions are shown in FIG. Figure 4 a is the retention rate of capsaicin at different salt concentrations, Figure 4 b is the average particle size of capsaicin at different salt concentrations, Figure 4 c is the ζ-potential of capsaicin at different salt concentrations. Curve E represents the Pickering emulsion prepared in Example 1, curve F represents the Pickering emulsion prepared in Comparative Example 1, and curve G represents the Pickering emulsion prepared in Comparative Example 2. It can be seen from the figure that the Pickering emulsion prepared in Example 1 has the highest retention rate of capsaicin at different salt concentrations, the smallest average particle size, and the highest absolute value of ζ-potential, indicating that the Pickering emulsion prepared in Example 1 has the best stability and the best protective effect on capsaicin.

[0065] The retention rate of capsaicin was 100% under the condition of NaCl concentration of 0mmol / L; the retention rate of capsaicin was 99% under the condition of NaCl concentration of 30mmol / L; the retention rate of capsaicin was 98% under the condition of NaCl concentration of 50mmol / L; the retention rate of capsaicin was 97% under the condition of NaCl concentration of 100mmol / L; the retention rate of capsaicin was 92% under the condition of NaCl concentration of 200mmol / L; the retention rate of capsaicin was 90% under the condition of NaCl concentration of 300mmol / L; the retention rates of capsaicin in comparative examples 1-2 were 73% and 71% respectively;

[0066] The average particle size of the emulsion was 79.66nm when the NaCl concentration was 0mmol / L; the average particle size of the emulsion was 90.63nm when the NaCl concentration was 30mmol / L; the average particle size of the emulsion was 117.97nm when the NaCl concentration was 50mmol / L; the average particle size of the emulsion was 369.93nm when the NaCl concentration was 100mmol / L; the average particle size of the emulsion was 881.96nm when the NaCl concentration was 200mmol / L; the average particle size of the emulsion was 1258.67nm when the NaCl concentration was 300mmol / L.

[0067] The ζ-potential of the emulsion is -20.36mv when the NaCl concentration is 0mmol / L; the ζ-potential of the emulsion is -21.7mv when the NaCl concentration is 30mmol / L; the ζ-potential of the emulsion is -18.66mv when the NaCl concentration is 50mmol / L; the ζ-potential of the emulsion is -11.92mv when the NaCl concentration is 100mmol / L; the ζ-potential of the emulsion is -5.55mv when the NaCl concentration is 200mmol / L; the ζ-potential of the emulsion is -1.26mv when the NaCl concentration is 300mmol / L.

[0068] Figure 5 The capsaicin retention rate, average particle size and ζ-potential diagram of the composite nanoparticle-stabilized capsaicin Pickering emulsion prepared in Example 1 and Comparative Examples 1-2 under different temperature conditions are shown in FIG. Figure 5 a is the retention rate of capsaicin at different temperatures, Figure 5 b is the average particle size of capsaicin at different temperatures, Figure 5 c is the ζ-potential of capsaicin at different temperatures. Curve E represents the Pickering emulsion prepared in Example 1, Curve F represents the Pickering emulsion prepared in Comparative Example 1, and Curve G represents the Pickering emulsion prepared in Comparative Example 2. It can be seen from the figure that at a temperature of 90°C, the capsaicin retention rates of Example 1 and Comparative Examples 1-2 are 87%, 71%, and 72%, respectively; the Pickering emulsion prepared in Example 1 has the highest retention rate of capsaicin, the smallest average particle size, and the highest absolute value of ζ-potential under different temperature conditions, indicating that the Pickering emulsion prepared in Example 1 has the best stability and the best protective effect on capsaicin.

[0069] Figure 6 The capsaicin retention rate, average particle size and ζ-potential diagram of the composite nanoparticle-stabilized capsaicin Pickering emulsion prepared in Example 1 and Comparative Examples 1-2 under different UV irradiation times are shown in FIG. Figure 6a is the retention rate of capsaicin at different UV irradiation times, Figure 6 b is the average particle size of capsaicin under different UV irradiation times, Figure 6 c is the ζ-potential of capsaicin under different UV irradiation times. Curve E represents the Pickering emulsion prepared in Example 1, Curve F represents the Pickering emulsion prepared in Comparative Example 1, and Curve G represents the Pickering emulsion prepared in Comparative Example 2. It can be seen from the figure that after 12 hours of UV irradiation, the capsaicin retention rates of Example 1 and Comparative Examples 1-2 are 88%, 64%, and 65%, respectively. The Pickering emulsion prepared in Example 1 has the highest retention rate of capsaicin, the smallest average particle size, and the highest absolute value of ζ-potential under different UV irradiation times, indicating that the Pickering emulsion prepared in Example 1 has the best stability and the best protective effect on capsaicin.

[0070] The composite nanoparticle-stabilized capsaicin Pickering emulsions prepared in Example 1 and Comparative Examples 1-2 were subjected to in vitro digestion tests. The simulated gastric fluid (SGF) was mainly composed of pepsin, NaCl and HCl, the pH value was adjusted to 2.0, and the culture was shaken at 37°C for 2 hours. The simulated intestinal fluid (SIF) was mainly composed of CaCl 2 , NaCl, trypsin, bile salt, adjust pH to 6.8 with 1 mol / L NaOH, and stir overnight at 4°C. Add capsaicin oil solution and Pickering emulsion prepared in Example 1 and Comparative Examples 1-2 in the same volume as the simulated gastric juice to 4 simulated gastric juices, adjust the pH of the simulated gastric juice to 7.0 after 120 minutes of digestion, add simulated intestinal juice, and digest for 120 minutes. During this period, the cumulative release of capsaicin was measured every 40 minutes, and the formula is:

[0071]

[0072] Among them, "W t " is the content of capsaicin in simulated gastric or intestinal fluid at time "t", "W 0 " is the initial capsaicin content. Figure 7 As shown, the amount of capsaicin released in simulated gastric juice after emulsion loading is small, and the unloaded capsaicin oil solution is quickly released in gastric juice and begins to degrade over time. The capsaicin oil solution continues to degrade in the intestinal juice, while the capsaicin loaded by emulsion is quickly released in the intestinal juice and begins to degrade slowly over time. Therefore, the capsaicin loaded by emulsion can be released in the intestine, reducing the adverse effects on the capsaicin before reaching the intestine.

[0073] In the present invention, whey protein and carboxylated nanocellulose are used to prepare solid nanoparticles by vortexing, and then ultrasonic homogenization is carried out to successfully load capsaicin. In the present invention, the specific technical indexes for the preparation of Pickering emulsion under this method are determined. Moreover, the prepared Pickering emulsion can better prevent capsaicin from being degraded under adverse conditions such as light, high temperature, and high salt, and extend its storage period. The prepared Pickering emulsion will degrade in the intestine and release a large amount of capsaicin in the intestine, improving the bioavailability of capsaicin.

[0074] The above are only the preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. For those skilled in the art of this technology, changes or substitutions that can be easily thought of are also regarded as the protection scope of the present invention.

Claims

1. A method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion, characterized in that: include: Step 1: Dispersing whey protein and carboxylated nanocellulose in deionized water respectively, and then mixing and drying the two to obtain composite nanoparticles; Step 2: adding the citric acid solution to the composite nanoparticles in step 1 to prepare a nanoparticle suspension; Step 3: dissolving capsaicin powder in soybean oil and performing ultrasonic homogenization to obtain a capsaicin oil solution; Step 4: then add the nanoparticle suspension of step 2 into the capsaicin oil solution of step 3, mix, and perform ice bath ultrasonic homogenization to obtain a composite nanoparticle-stabilized capsaicin Pickering emulsion.

2. The method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion according to claim 1, characterized in that: The mass ratio of whey protein and carboxylated nanocellulose described in step 1 is (1-4):(1-4).

3. The method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion according to claim 1, characterized in that: The concentration of the citric acid solution in step 2 is 10 mmol / L.

4. The method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion according to claim 1, characterized in that: In step 2, citric acid is added to prepare a solution, and the pH value of the solution is adjusted to 3.0±0.1 with hydrochloric acid.

5. The method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion according to claim 1, characterized in that: In step 2, the concentration of the nanoparticle suspension is 0.1-6%.

6. The method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion according to claim 1, characterized in that: The mass mg of the capsaicin powder described in step 3: the volume mL of soybean oil is 1:

1.

7. The method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion according to claim 1, characterized in that: The conditions of ultrasonic homogenization in step 3 are: power of 650 W, temperature of 20° C., and time of 30 min.

8. The method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion according to claim 1, characterized in that: The mixing time in step 4 is 5 min.

9. The method for preparing a composite nanoparticle-stabilized capsaicin Pickering emulsion according to claim 1, characterized in that: The conditions of ice bath ultrasonic homogenization in step 4 are: power of 650 W, ultrasonication for 2 seconds with an interval of 2 seconds, and ultrasonication time of 5-20 minutes.

10. The capsaicin Pickering emulsion stabilized by composite nanoparticles obtained by the preparation method of claim 1.

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