High-biocompatibility pH response type Pickering emulsion and preparation method thereof

Abstract

The invention discloses a high-biocompatibility pH response type Pickering emulsion and a preparation method thereof, and relates to the technical field of food and materials. An interfacial film with high mechanical strength is constructed by adopting electrostatic interaction and hydrophilic-hydrophobic complementary characteristics between the hydrophobic shellac nanoparticles carrying negative charges and the hydrophilic cationic colloidal particles carrying positive charges, and the prepared emulsion has good viscoelasticity and stability. In addition, due to the unique solubility of the shellac nanoparticles, the Pickering emulsion prepared by the preparation method disclosed by the invention has excellent pH responsiveness. The preparation method of the Pickering emulsion is convenient and simple, the stabilizer is wide in source and low in price, the biocompatibility of the emulsion is high, and the Pickering emulsion has wide application prospects in the aspects of food, medicine, materials and the like.

Description

Technical Field

[0001] The present invention relates to the field of food technology and material technology, and in particular to a highly biocompatible pH-responsive Pickering emulsion and a preparation method thereof. Background Art

[0002] Emulsions are dispersed systems composed of two immiscible liquids. Due to the high surface energy between the liquids, emulsions are usually thermodynamically unstable systems. Therefore, surfactants are usually added to reduce the oil-water interfacial energy to improve the thermodynamic stability of the emulsion. Unlike traditional surfactant-stabilized emulsions, Pickering emulsions, new emulsions stabilized by solid particles, usually have good stability. Compared with highly toxic and difficult to degrade inorganic particles, environmentally friendly food-grade particles show potential application prospects. To this end, a variety of new bio-based Pickering stabilizers have been developed one after another. At present, the natural materials that can be used as Pickering stabilizers mainly include polysaccharides, proteins, polyphenols and lipids. However, due to the limited wettability of bio-based colloidal particles themselves, chemical, physical or biological methods are usually required to modify their surface before they can be used to stabilize Pickering emulsions. For example, the patent with publication number CN113892632A discloses a method for preparing Pickering emulsion using modified soybean globulin microgel, in which the extracted soybean globulin powder is subjected to a combined heating treatment (heating in a water bath at 95°C for 5-30 min), an ultrasonic treatment (0-70% amplitude treatment at 20 kHz for 0-12 min) and a pH shift treatment (first adjusting the pH to 12, stirring for 1 h, then adjusting the pH to 7, and maintaining for 1 h) to prepare the modified soybean globulin microgel. The process of preparing the emulsifier is relatively cumbersome, which is not conducive to the production and application of the emulsion.

[0003] Recently, Pickering emulsions co-stabilized by binary particles have attracted widespread attention from researchers. Relying on relatively simple binding modes between different particles, such as reactions of different functional groups, hydrophobic interactions, and electrostatic interactions, the interfacial adsorption characteristics of the particles can be adjusted, thereby being able to synergistically stabilize the Pickering emulsions. This not only achieves the simple and rapid preparation of particle stabilizers, but also can give Pickering emulsions unexpected properties. The patent with publication number CN113081868A discloses a multi-Pickering emulsion synergistically stabilized by alcohol-soluble protein nanoparticles and nano-cellulose and a preparation method thereof. Although the emulsion has a wide oil phase range, it does not have pH responsiveness, which leads to application limitations. Therefore, the construction of pH-responsive emulsions is of great significance for their application in the field of drug and active substance delivery. The patent with publication number CN116515307A discloses an emulsion with sensitive pH response ability and strong salt resistance and its preparation method, wherein quaternary ammonium lignin is obtained by quaternizing alkali lignin with 3-chloro-2-hydroxypropyltrimethylammonium chloride, oxidized nanocellulose is prepared by oxidizing wood cellulose with TEMPO / NaC10 / NaBr, and the synergistic effect between the two is used to construct a Pickering emulsion. The emulsion not only has good stability, but also has sensitive pH responsiveness and strong salt resistance. However, toxic and harmful substances are likely to be introduced during the modification and oxidation process, and the preparation process of the composite particles is slightly cumbersome, which greatly limits the application of the emulsion, and it is urgent to develop a pH-responsive Pickering emulsion with good biodegradability and biocompatibility. Summary of the invention

[0004] The purpose of the present invention is to provide a highly biocompatible pH-responsive Pickering emulsion and a preparation method thereof. The preparation method of the emulsion is simple and rapid, the emulsion has good stability, pH responsiveness and strong salt tolerance, and the raw materials used are all biodegradable and biocompatible.

[0005] The present invention first provides a method for preparing a highly biocompatible pH-responsive Pickering emulsion, comprising:

[0006] Step 1: preparing shellac nanoparticle dispersion;

[0007] Step 2: treating the hydrophilic cationic powder by ultrasonic treatment to obtain a hydrophilic cationic colloidal particle dispersion;

[0008] Step 3: adding the hydrophilic cationic colloidal particle dispersion of step 2 to the shellac nanoparticle dispersion of step 1 and mixing them to obtain a Pickering emulsifier;

[0009] Step 4: Compound the Pickering emulsifier in step 3 with the oil phase, place under a high-speed shearing machine for shearing, and obtain a pH-responsive Pickering emulsion.

[0010] Preferably, the preparation method of the shellac nanoparticle dispersion in step 1 comprises:

[0011] Shellac is dissolved in a solvent and stirred to obtain a shellac solution. The shellac solution is centrifuged, and the obtained centrifuge is subjected to anti-solvent precipitation and rotary evaporation to obtain a shellac nanoparticle dispersion.

[0012] Preferably, the concentration of the shellac nanoparticle dispersion is 1.0-10.0 wt %.

[0013] Preferably, the hydrophilic cationic powder in step 2 is one or more of chitin, chitosan or ε-polylysine.

[0014] Preferably, the concentration of the hydrophilic cationic colloidal particle dispersion is 1.0-10.0 wt %.

[0015] Preferably, the volume ratio of the hydrophilic cationic colloidal particle dispersion to the shellac nanoparticle dispersion in step three is 1:99-99:1.

[0016] Preferably, the oil phase in step 4 is soybean oil, peanut oil, corn oil, corn germ oil, linseed oil, castor oil, rapeseed oil, sunflower oil, olive oil, camellia oil, coconut oil, rice bran oil, Antarctic krill oil, medium-chain triglycerides, essential oils or oils containing functionally active substances.

[0017] Preferably, the functionally active substance in the oil containing functionally active substances is curcumin, ginsenoside, astaxanthin, quercetin, carotene, resveratrol, phytosterols, probiotics, vitamins, catechins, diglycerides, soy isoflavones or tea polyphenols.

[0018] Preferably, the volume ratio of the oil phase to the Pickering emulsifier in step 4 is 1:99-99:1.

[0019] The present invention also provides a highly biocompatible pH-responsive Pickering emulsion obtained by the preparation method.

[0020] Beneficial effects of the present invention

[0021] The present invention provides a highly biocompatible pH-responsive Pickering emulsion and a preparation method thereof. The emulsion uses shellac nanoparticles as hydrophobic anionic colloid particles and is mixed with hydrophilic cationic colloid particles as Pickering emulsifiers, and is prepared with an oil phase by a high-energy mixing method. The present invention utilizes the electrostatic interaction and hydrophilic-hydrophobic complementary properties between binary colloid particles to promote the co-adsorption of the Pickering emulsifier at the oil-water interface, forming a dense interface film with high mechanical strength and a three-dimensional network structure, thereby preparing a Pickering emulsion with good stability and high viscoelasticity. Among them, one or two of the binary colloid particles are pH-responsive particles, which have unique response behaviors at different pH values, thereby giving the emulsion good pH responsiveness. The emulsion prepared by the present invention has obvious pH responsiveness, strong salt resistance and excellent viscoelasticity. This emulsion is not only environmentally friendly and highly biocompatible, but also has a simple and rapid preparation method and mild reaction conditions, making it suitable for large-scale industrial production. The constructed Pickering emulsion can be used in the delivery of functional oils and active substances, and has broad application prospects in biomedicine, agriculture, environmental science, food industry, cosmetics and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a transmission electron microscope (TEM) image of shellac nanoparticles (SNPs) of Example 1;

[0023] Figure 2 is a transmission electron microscope (TEM) image of chitin nanocrystals (ChNCs) of Example 1;

[0024] Figure 3 The appearance and microstructure of Pickering emulsions at different colloidal particle ratios of Example 1 (S5C1), Example 4 (S3C1), Example 5 (S1C1), Example 7 (S1C3), Example 8 (S1C5), Comparative Example 1 (SNPs) and Comparative Example 2 (ChNCs);

[0025] Figure 4 It is a graph showing changes in Zeta potential of Pickering emulsions at different colloidal particle ratios of Example 1 (S5C1), Example 4 (S3C1), Example 5 (S1C1), Example 7 (S1C3), Example 8 (S1C5), Comparative Example 1 (SNPs) and Comparative Example 2 (ChNCs);

[0026] Figure 5 This is a confocal laser scanning microscopy (CLSM) image of the Pickering emulsion of SNPs / ChNCs 5:1 (S5C1) in Example 1;

[0027] Figure 6This is a cryo-scanning electron microscope (cryo-SEM) image of the Pickering emulsion of SNPs / ChNCs 5:1 (S5C1) of Example 1;

[0028] Figure 7 The appearance and optical microscope (OM) images of the emulsion when the ratio of SNPs / ChNCs in Example 1 is 5:1 (S5C1) and the pH values ​​are 3, 5, 7, 9, and 11, respectively;

[0029] Figure 8 The appearance and optical microscope (OM) images of emulsions with different ionic strengths (0 mM, 50 mM, 100 mM, 300 mM, 500 mM) added to the SNPs / ChNCs ratio of 5:1 (S5C1) in Example 1. DETAILED DESCRIPTION

[0030] The present invention first provides a method for preparing a highly biocompatible pH-responsive Pickering emulsion, comprising:

[0031] Step 1: preparing shellac nanoparticle dispersion;

[0032] Step 2: treating the hydrophilic cationic powder by ultrasonic treatment to obtain a hydrophilic cationic colloidal particle dispersion;

[0033] Step 3: adding the hydrophilic cationic colloidal particle dispersion of step 2 to the shellac nanoparticle dispersion of step 1 and mixing them to obtain a Pickering emulsifier;

[0034] Step 4: Compound the Pickering emulsifier in step 3 with the oil phase and place it under a high-speed shearing machine for shearing to obtain a pH-responsive Pickering emulsion. The shellac nanoparticles, cationic colloid particles and Pickering emulsion are obtained by the following steps:

[0035] According to the present invention, a shellac nanoparticle dispersion is first prepared. The method for preparing the shellac nanoparticle dispersion preferably comprises:

[0036] Dissolve shellac in a solvent and stir, the solvent is preferably an 80-99.5% ethanol solution, the stirring time is 6-36 hours, the obtained shellac solution is preferably centrifuged at 3000-20000 rpm for 3-60 minutes to remove insoluble substances, the obtained centrifuged solution is poured into preferably 1000-2000 mL of deionized water for anti-solvent precipitation, and finally, the ethanol and excess water are removed by rotary evaporation by a rotary evaporator, preferably at a temperature of 50-90° C., to obtain a shellac nanoparticle dispersion, the concentration of the shellac nanoparticle dispersion is preferably 1.0-10.0wt%, more preferably 2.0wt%;

[0037] According to the present invention, the hydrophilic cationic powder obtained by different preparation methods is added to deionized water, preferably by ultrasonic treatment at 50-100W for 30-100min, to obtain a hydrophilic cationic colloidal particle dispersion, wherein the concentration of the hydrophilic cationic colloidal particle dispersion is preferably 1.0-10.0wt%, more preferably 2.0wt%; the hydrophilic cationic powder is preferably any one or more of chitin, chitosan or ε-polylysine, more preferably chitin;

[0038] According to the present invention, a hydrophilic cationic colloidal particle dispersion is directly added to a shellac nanoparticle dispersion and mixed to obtain a continuous aqueous phase with different Pickering emulsifier ratios, wherein the volume ratio of the hydrophilic cationic colloidal particle dispersion to the shellac nanoparticle dispersion in the aqueous phase is preferably 1:99-99:1, more preferably 5:1, 3:1, 1:1, 1:3 or 1:5.

[0039] According to the present invention, the aqueous phase containing shellac and cationic colloid particles is compounded with the oil phase, wherein the volume ratio of the oil phase to the aqueous phase is preferably 1:99-99:1, more preferably 6:4, 5:5 or 4:6, and the aqueous phase and the oil phase are placed in a high-speed shearing machine and preferably sheared at 3000-30000rpm for 0.5-30min to obtain a pH-responsive Pickering emulsion. The oil phase is preferably soybean oil, peanut oil, corn oil, corn germ oil, linseed oil, castor oil, rapeseed oil, sunflower oil, olive oil, camellia oil, coconut oil, rice bran oil, Antarctic krill oil, medium-chain triglycerides, essential oils or oils containing functional active substances, more preferably soybean oil, peanut oil or corn oil. The functional active substance in the oil containing functional active substances is curcumin, ginsenosides, astaxanthin, quercetin, carotene, resveratrol, phytosterols, probiotics, vitamins, catechins, diglycerides, soy isoflavones or tea polyphenols. The amount of the functional active substance added is preferably 0.1 wt% to 20.0 wt% of the oil.

[0040] According to the present invention, the method of compounding the water phase and the oil phase is not limited to shearing, but preferably includes other high-energy mixing methods such as stirring, high-pressure homogenization, and high-pressure microfluidization.

[0041] The present invention will be further described in detail below in conjunction with specific implementation modes and drawings, but the present invention is not limited to the following implementation modes.

[0042] Example 1

[0043] (1) Preparation of shellac nanoparticle dispersion: 12 g of shellac was dissolved in 95% ethanol solution and stirred for 24 h. The obtained shellac solution was centrifuged at 12000 rpm for 10 min to remove insoluble matter. The obtained shellac solution was poured into 1500 ml of deionized water for anti-solvent precipitation. Finally, ethanol and excess water were removed by rotary evaporation at 85° C. using a rotary evaporator to obtain a shellac nanoparticle dispersion with a concentration of 2.0 wt % (labeled as SNPs and corresponding to all figures of the Examples and Comparative Examples).

[0044] (2) Chitosan powder was added into deionized water and subjected to ultrasonic treatment at 100 W for 30 min to obtain a chitosan colloidal particle dispersion with a concentration of 2.0 wt % (labeled as ChNCs and corresponding to all figures of the embodiment and comparative example).

[0045] (3) The dispersion of step (2) was directly added to the dispersion of shellac nanoparticles to obtain a continuous phase (labeled as S5C1 and corresponding to all figures of the embodiment and comparative example) with a volume ratio of 5:1 between shellac nanoparticles and chitin dispersion, 12 ml of soybean oil was added, the ratio of oil phase to water phase was 5:5, and the mixture was placed on a high-speed shearing machine at 12000 rpm for 3 min to prepare a pH-responsive Pickering emulsion. The emulsion prepared above did not flow when placed upright or upside down, and had excellent stability.

[0046] Figure 1 This is a transmission electron microscope (TEM) image of shellac nanoparticles (SNPs) of Example 1. Figure 1 It can be seen that the present invention successfully prepared shellac nanoparticles (SNPs) showing a smooth spherical shape.

[0047] Figure 2 This is a transmission electron microscope (TEM) image of chitin nanocrystals (ChNCs) in Example 1. Figure 2 It can be seen that the present invention successfully prepared chitosan nanocrystals (ChNCs) in a disordered fiber shape.

[0048] Figure 5 This is a confocal laser scanning microscopy (CLSM) image of the Pickering emulsion of SNPs / ChNCs 5:1 (S5C1) in Example 1. Figure 6 This is a cryo-scanning electron microscopy (cryo-SEM) image of the Pickering emulsion with a ratio of SNPs / ChNCs of 5:1 (S5C1) in Example 1. Figure 6 A represents 30μm, Figure 6 B represents 10μm, Figure 6 C represents 5μm, Figure 6D represents 2 μm. It can be seen that further observation of SNPs / ChNCs at 5:1 by CLSM and cryo-SEM revealed that the two particles formed an interfacial film and a three-dimensional network structure at the oil-water interface, which effectively stabilized the emulsion.

[0049] pH responsiveness test of the emulsion prepared in Example 1: By using 1 mol / L NaOH or 2 mol / L HCl to add dropwise into a mixed solution of SNPs / ChNCs of 5:1 (S5C1), the pH values ​​were adjusted to 3, 5, 7, 9, and 11, respectively, and a pH-responsive Pickering emulsion was prepared according to the above emulsion preparation method.

[0050] Figure 7 The appearance and optical microscope (OM) images of the emulsion when the SNPs / ChNCs ratio of Example 1 is 5:1 (S5C1) and the pH values ​​are 3, 5, 7, 9 and 11, respectively. It can be seen that the emulsion does not flow whether it is turned upside down or not at pH 3, 5 and 7, and the emulsion particles are uniform in size and closely arranged under microscopic observation; the emulsion oil and water are separated at pH 9 and 11, and the emulsion oil droplets aggregate in large pieces under microscopic observation, indicating that the emulsion is pH responsive.

[0051] Salt tolerance test of the emulsion prepared in Example 1: pH-responsive Pickering emulsions were prepared according to the above method by adding 0 mM, 50 mM, 100 mM, 300 mM, and 500 mM salt ions (NaCl) to the mixed solution of SNPs / ChNCs at a ratio of 5:1 (S5C1). Figure 8 The appearance and optical microscope (OM) images of emulsions with different ionic strengths (0 mM, 50 mM, 100 mM, 300 mM, 500 mM) added at a ratio of SNPs / ChNCs of 5:1 (S5C1) in Example 1 show that, with the increase of ionic strength, although the emulsion droplets become slightly larger, it does not have much effect on the appearance of the emulsion and remains stable, indicating that the emulsion has strong salt resistance.

[0052] Example 2

[0053] The preparation of shellac nanoparticle dispersion was the same as in Example 1;

[0054] (1) Chitosan powder was added into deionized water and subjected to 100 W ultrasonic treatment for 30 min to obtain a chitosan colloidal particle dispersion with a concentration of 2.0 wt %.

[0055] (2) The dispersion of step (1) is directly added to the dispersion of shellac nanoparticles to obtain a continuous phase with a volume ratio of shellac nanoparticles to chitosan dispersion of 5:1, 12 ml of soybean oil is added, the ratio of oil phase to water phase is 5:5, and the mixture is placed on a high-speed shearing machine at 12000 rpm for 3 minutes to prepare a pH-responsive Pickering emulsion. The emulsion prepared above does not flow when placed upright or upside down, and has excellent stability.

[0056] Example 3

[0057] The preparation of shellac nanoparticle dispersion was the same as in Example 1;

[0058] (1) The obtained ε-polylysine powder was added into deionized water, and an ε-polylysine colloidal particle dispersion with a concentration of 2.0 wt% was obtained by ultrasonic treatment at 100 W for 30 min.

[0059] (2) The dispersion of step (1) is directly added to the dispersion of shellac nanoparticles to obtain a continuous phase with a volume ratio of 5:1 between shellac nanoparticles and ε-polylysine dispersion, 12 ml of soybean oil is added, the ratio of oil phase to water phase is 5:5, and the mixture is placed on a high-speed shearing machine at 12000 rpm for 3 minutes to prepare a pH-responsive Pickering emulsion. The emulsion prepared above does not flow when placed upright or upside down, and has excellent stability.

[0060] Example 4

[0061] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 3:1 (labeled as S3C1 and corresponding to all figures of the examples and comparative examples) was prepared, 12 ml of soybean oil was added, the ratio of the oil phase to the water phase was 5:5, and the mixture was placed in a high-speed shearing machine at 12000 rpm for 3 minutes to prepare a pH-responsive Pickering emulsion. The emulsion prepared above did not stratify when placed upright, did not flow when placed upside down, and had good stability.

[0062] Example 5

[0063] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 1:1 (labeled as S1C1 and corresponding to all figures of the embodiment and comparative example) was prepared, 12 ml of soybean oil was added, the ratio of oil phase to water phase was 5:5, and the mixture was placed in a high-speed shearing machine at 12000 rpm for 3 minutes to prepare a pH-responsive Pickering emulsion. The emulsion prepared above did not stratify when placed upright, did not flow when placed upside down, and had good stability.

[0064] Example 6

[0065] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 1:3 (labeled as S1C3 and corresponding to all figures of the examples and comparative examples) was prepared, 12 ml of soybean oil was added, the ratio of the oil phase to the water phase was 5:5, and the mixture was placed in a high-speed shearing machine at 12000 rpm for 3 minutes to prepare a pH-responsive Pickering emulsion. The emulsion prepared above slightly stratified when placed upright, flowed when placed inverted, and had good stability.

[0066] Example 7

[0067] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 1:5 (labeled as S1C5 and corresponding to all figures of the examples and comparative examples) was prepared, 12 ml of soybean oil was added, the ratio of the oil phase to the water phase was 5:5, and the mixture was placed in a high-speed shearing machine at 12000 rpm for 3 minutes to prepare a pH-responsive Pickering emulsion. The emulsion prepared above was slightly stratified when placed upright, flowed when placed inverted, and had good stability.

[0068] Example 8

[0069] The preparation steps and conditions are the same as those in Example 1, except that soybean oil is replaced with corn oil to prepare a pH-responsive Pickering emulsion. The emulsion prepared above does not flow when placed upright or upside down, and has excellent stability.

[0070] Example 9

[0071] The preparation steps and conditions are the same as those in Example 1, except that soybean oil is replaced with peanut oil to prepare a pH-responsive Pickering emulsion. The emulsion prepared above does not flow when placed upright or upside down, and has excellent stability.

[0072] Example 10

[0073] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 5:1 was prepared, 14.4 ml of soybean oil was added, the ratio of oil phase to water phase was 6:4, and the mixture was sheared at 12000 rpm for 3 min on a high-speed shearing machine to prepare a pH-responsive Pickering emulsion. The emulsion prepared above did not stratify when placed upright, flowed when placed inverted, and had good stability.

[0074] Embodiment 11

[0075] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 5:1 was prepared, 9.6 ml of soybean oil was added, the ratio of oil phase to water phase was 4:6, and the mixture was sheared at 12000 rpm for 3 min on a high-speed shearing machine to prepare a pH-responsive Pickering emulsion. The emulsion prepared above did not separate oil and water when placed upright, flowed when placed inverted, and had good stability.

[0076] Example 12

[0077] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 5:1 was prepared, 12 ml of soybean oil was added, the ratio of the oil phase to the water phase was 5:5, and the mixture was sheared at 15000 rpm for 1 min on a high-speed shearing machine to prepare a pH-responsive Pickering emulsion. The emulsion prepared above was slightly free of stratification when placed upright, and did not flow when placed upside down, and had good stability.

[0078] Example 13

[0079] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 5:1 was prepared, 12 ml of soybean oil was added, the ratio of the oil phase to the water phase was 5:5, and the mixture was sheared at 13000 rpm for 2.5 min on a high-speed shearing machine to obtain a pH-responsive Pickering emulsion. The emulsion prepared above did not stratify when placed upright, did not flow when placed upside down, and had good stability.

[0080] Embodiment 14

[0081] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 5:1 was prepared, 12 ml of Antarctic krill oil was added, the ratio of the oil phase to the water phase was 5:5, and the mixture was sheared at 12000 rpm for 3 minutes on a high-speed shearing machine to prepare a pH-responsive Pickering emulsion. The emulsion prepared above will not stratify when placed upright, will not flow when placed upside down, and has good stability.

[0082] Embodiment 15

[0083] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 5:1 was prepared, 12 ml of oregano essential oil was added, the ratio of the oil phase to the water phase was 5:5, and the mixture was sheared at 12000 rpm for 3 min on a high-speed shearing machine to prepare a pH-responsive Pickering emulsion. The emulsion prepared above will not stratify when placed upright, will not flow when placed upside down, and has good stability.

[0084] Example 16

[0085] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 5:1 was prepared, 12 ml of soybean oil rich in curcumin was added, the ratio of the oil phase to the water phase was 5:5, and the mixture was sheared at 12000 rpm for 3 min on a high-speed shearing machine to prepare a pH-responsive Pickering emulsion. The emulsion prepared above did not stratify when placed upright, did not flow when placed upside down, and had good stability.

[0086] Embodiment 17

[0087] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 5:1 was prepared, 12 ml of soybean oil rich in ginsenosides was added, the ratio of oil phase to water phase was 5:5, and the mixture was sheared at 12000 rpm for 3 min on a high-speed shearing machine to prepare a pH-responsive Pickering emulsion. The emulsion prepared above did not stratify when placed upright, did not flow when placed upside down, and had good stability.

[0088] Embodiment 18

[0089] According to the preparation and conditions of Example 1, a continuous phase with a ratio of SNPs / ChNCs of 5:1 was prepared, 12 ml of astaxanthin-rich soybean oil was added, the ratio of the oil phase to the water phase was 5:5, and the mixture was sheared at 12000 rpm for 3 min on a high-speed shearing machine to prepare a pH-responsive Pickering emulsion. The emulsion prepared above did not stratify when placed upright, did not flow when placed upside down, and had good stability.

[0090] Comparative Example 1

[0091] The 2.0 wt% SNPs prepared in Example 1 were used alone as a stabilizer, 12 ml of soybean oil was added, the oil phase and water phase ratio was 5:5, and the mixture was sheared at 12000 rpm for 3 min to prepare a Pickering emulsion. The emulsion prepared above showed oil-water separation and had extremely poor stability.

[0092] Comparative Example 2

[0093] 2.0 wt% ChNCs prepared in Example 1 were used as stabilizers alone, 12 ml soybean oil was added, the oil phase and water phase ratio was 5:5, and the mixture was sheared at 12000 rpm for 3 min to prepare a Pickering emulsion. The emulsion prepared above showed oil-water separation and had extremely poor stability.

[0094] Figure 3The appearance and microstructure of the emulsions at different colloidal particle ratios of Example 1 (S5C1), Example 4 (S3C1), Example 5 (S1C1), Example 6 (S1C3), Example 7 (S1C5), Comparative Example 1 (SNPs) and Comparative Example 2 (ChNCs) of the present invention show that neither chitosan nanocrystals nor shellac nanoparticles alone can stabilize the Pickering emulsion, and both exhibit oil-water separation. However, the emulsion droplets under the synergistic stabilization of the two are relatively uniform in size and tightly arranged, showing better stability.

[0095] Figure 4 This is a graph showing changes in the Zeta potential of Pickering emulsions at different colloidal particle ratios in Example 1 (S5C1), Example 4 (S3C1), Example 5 (S1C1), Example 7 (S1C3), Example 8 (S1C5), Comparative Example 1 (SNPs) and Comparative Example 2 (ChNCs) of the present invention. It can be seen that the Zeta potential of the emulsion changes from negative to positive as the amount of ChNCs increases, indicating that an electrostatic interaction occurs between the two.

[0096] The implementation results of Example 1, Example 2 and Example 3 show that the stability of the emulsion stabilized by shellac nanoparticles and different cationic nanoparticles is excellent, indicating that different cationic nanomaterials have no effect on the formation of pH-responsive Pickering emulsions. In Example 1, Example 8 and Example 9, different types of oils are used to prepare emulsions, and the emulsion stability is excellent, indicating that the oil type will not affect the formation of pH-responsive Pickering emulsions. In Example 14 and Example 15, the Pickering emulsions prepared by replacing the soybean oil in Example 1 with functional oils (Antarctic krill oil, oregano essential oil) have good stability, indicating that the emulsion can be used to load functional oils. In Example 16, Example 17 and Example 18, functional active substances (curcumin, ginsenosides, astaxanthin) are added to soybean oil on the basis of Example 1, and the prepared emulsions all have good stability, indicating that the emulsion can be used to load functional active substances.

Claims

1. A method for preparing a highly biocompatible pH-responsive Pickering emulsion, characterized in that: include: Step 1: preparing shellac nanoparticle dispersion; Step 2: treating the hydrophilic cationic powder by ultrasonic treatment to obtain a hydrophilic cationic colloidal particle dispersion; Step 3: adding the hydrophilic cationic colloidal particle dispersion of step 2 to the shellac nanoparticle dispersion of step 1 and mixing them to obtain a Pickering emulsifier; Step 4: Compound the Pickering emulsifier in step 3 with the oil phase, place under a high-speed shearing machine for shearing, and obtain a pH-responsive Pickering emulsion.

2. The method for preparing a highly biocompatible pH-responsive Pickering emulsion according to claim 1, characterized in that: Step 1 The preparation method of shellac nanoparticle dispersion comprises: Shellac is dissolved in a solvent and stirred to obtain a shellac solution. The shellac solution is centrifuged, and the obtained centrifuge is subjected to anti-solvent precipitation and rotary evaporation to obtain a shellac nanoparticle dispersion.

3. The method for preparing a highly biocompatible pH-responsive Pickering emulsion according to claim 2, characterized in that: The concentration of the shellac nanoparticle dispersion is 1.0-10.0 wt %.

4. The method for preparing a highly biocompatible pH-responsive Pickering emulsion according to claim 1, characterized in that: The hydrophilic cationic powder in step 2 is one or more of chitin, chitosan or ε-polylysine.

5. The method for preparing a highly biocompatible pH-responsive Pickering emulsion according to claim 1, characterized in that: The concentration of the hydrophilic cationic colloidal particle dispersion is 1.0-10.0 wt %.

6. The method for preparing a highly biocompatible pH-responsive Pickering emulsion according to claim 1, characterized in that: The volume ratio of the hydrophilic cationic colloidal particle dispersion to the shellac nanoparticle dispersion in step three is 1:99-99:

1.

7. The method for preparing a highly biocompatible pH-responsive Pickering emulsion according to claim 1, characterized in that: The oil phase described in step 4 is soybean oil, peanut oil, corn oil, corn germ oil, linseed oil, castor oil, rapeseed oil, sunflower oil, olive oil, camellia oil, coconut oil, rice bran oil, Antarctic krill oil, medium-chain triglycerides, essential oils or oils containing functional active substances.

8. The method for preparing a highly biocompatible pH-responsive Pickering emulsion according to claim 7, characterized in that: The functional active substance in the oil containing functional active substances is curcumin, ginsenoside, astaxanthin, quercetin, carotene, resveratrol, phytosterol, probiotics, vitamins, catechin, diglyceride, soy isoflavone or tea polyphenols.

9. The method for preparing a highly biocompatible pH-responsive Pickering emulsion according to claim 1, characterized in that: The volume ratio of the oil phase to the Pickering emulsifier in step 4 is 1:99-99:

1.

10. The highly biocompatible pH-responsive Pickering emulsion obtained by the preparation method of claim 1.

Images