Capsaicin-embedded emulsion and preparation method thereof

Abstract

The invention belongs to the technical field of emulsion preparation, and discloses capsaicin-embedded emulsion and a preparation method thereof. The emulsion is an oil-in-water emulsion, a water phase is a vegetable protein-modified cellulose nanofiber solution, an oil phase is a vegetable oil solution in which capsaicin is dissolved, the oil phase is uniformly dispersed in water in a form of extremely small liquid drops, and the modified cellulose nanofibers form a compact network structure on the surfaces of the liquid drops, so that a hydrophobic core space is expanded, and a hydrophobic effect is improved. The stability of an emulsion system is maintained, so that the emulsion shows higher capsaicin embedding efficiency. By adjusting the high-pressure plasma modification conditions of the cellulose nanofibers, the in-vitro release rate of capsaicin in the emulsion is controlled to be 10%-20%, and controllable release of capsaicin in the emulsion is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of emulsion preparation, and particularly relates to an emulsion for encapsulating capsaicin and a preparation method thereof. Background Art

[0002] Capsaicin, as the main active ingredient in chili peppers, has significant pharmacological effects such as analgesia, anti - inflammation, and antipruritic, and has broad application prospects in the fields of medicine, health food, etc. However, capsaicin is a fat - soluble substance, almost insoluble in cold water, and is easily degraded by the extreme pH environment and digestive enzymes in the digestive process, resulting in a bioavailability of less than 10%. Emulsion encapsulation technology can be used for the encapsulation, delivery, and protection of active ingredients, and can also control the release, digestion, and absorption of active ingredients, thereby improving the bioavailability of active ingredients. However, the existing emulsion systems are easily affected by the external environment, have poor stability, have poor encapsulation effect when used for capsaicin, and it is difficult to control the release rate of the emulsion encapsulating capsaicin in the stomach, and even easy to have burst release, thus limiting the bioavailability of capsaicin.

[0003] In view of this, the present invention is specifically proposed. Summary of the Invention

[0004] The purpose of the present invention is to provide an emulsion for encapsulating capsaicin and a preparation method thereof, which can significantly improve the encapsulation effect of capsaicin in the emulsion and simultaneously achieve the controlled release of capsaicin.

[0005] To achieve the above - mentioned purpose, the first technical solution adopted by the present invention is: An emulsion for encapsulating capsaicin, wherein the aqueous phase is a plant protein - modified cellulose nanofiber solution, and the oil phase is a vegetable oil solution dissolved with capsaicin.

[0006] Preferably, the concentration of capsaicin in the vegetable oil solution dissolved with capsaicin is 0.0004 - 0.001 mol / L. Capsaicin is a solid material, insoluble in water but soluble in oil, so it is dissolved in vegetable oil as the oil phase of the emulsion. The vegetable oil can be selected from common edible vegetable oils, such as sunflower oil, peanut oil, sesame oil, soybean oil, corn oil, etc., and sunflower oil is preferably used.

[0007] Preferably, the plant protein - modified cellulose nanofiber solution is obtained by mixing a modified cellulose nanofiber solution and a plant protein solution according to a mass ratio of 1 - 5:20.

[0008] Preferably, the mass fraction of the modified cellulose nanofiber solution is 4 - 8%.

[0009] Preferably, the mass fraction of the plant protein solution is 2-7%. The plant protein solution can be prepared from common plant proteins, such as peanut protein, pea protein, quinoa protein, chickpea protein, etc., and preferably chickpea protein.

[0010] Preferably, the volume ratio of the aqueous phase to the oil phase is 1-3:9.

[0011] The second technical solution adopted in the present invention is: A method for preparing an emulsion encapsulating capsaicin, characterized by comprising the following steps: Subject the cellulose nanofiber solution to high-pressure plasma treatment to obtain a modified cellulose nanofiber solution, and mix it with the plant protein solution to obtain an aqueous phase; Dissolve capsaicin in vegetable oil to obtain an oil phase; Mix the oil phase and the aqueous phase, and perform high-pressure homogenization treatment to obtain an oil-in-water emulsion.

[0012] Preferably, the high-pressure plasma treatment conditions are: jet discharge mode, pressure of 150-200 MPa, voltage of 4-11 kV, frequency of 34-57 kHz, and time of 4-8 min.

[0013] Preferably, the pressure of the high-pressure homogenization treatment is 90-130 MPa, the rotation speed is 11000-13000 rpm, and the time is 2-4 min.

[0014] Preferably, the mass fraction of the modified cellulose nanofiber solution is 4-8%.

[0015] Preferably, the mass fraction of the plant protein solution is 2-7%.

[0016] Preferably, the mass ratio of the modified cellulose nanofiber solution to the plant protein solution is 1-5:20.

[0017] Preferably, the volume ratio of the aqueous phase to the oil phase is 1-3:9.

[0018] Preferably, the concentration of capsaicin in the oil phase is 0.0004-0.001 mol / L.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. The emulsion encapsulating capsaicin provided by the present invention is an oil-in-water emulsion. In this emulsion system, the vegetable oil dissolved with capsaicin is uniformly dispersed in water in the form of extremely small droplets. The modified cellulose nanofibers form a tight network structure on the surface of the droplets, expanding the space of the hydrophobic core and maintaining the stability of the emulsion system. The emulsion exhibits a higher capsaicin encapsulation efficiency.

[0020] 2. By adjusting the high-pressure plasma modification conditions of cellulose nanofibers, the present invention controls the in vitro release rate of capsaicin in the emulsion between 10% and 20%, achieving the controlled release of capsaicin in the emulsion.

[0021] 3. The preparation method of the emulsion encapsulating capsaicin provided by the present invention is efficient and simple, which helps to expand the high-value application scenarios of capsaicin. Detailed implementation manners

[0022] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in combination with specific implementation manners. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention. For those not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0023] It should be noted that the centrifugation method and the ultrasonic method used in the following implementation manners are the corresponding methods commonly used in the art and do not require special limitation. The specific methods given in the examples are only examples, and those skilled in the art can select appropriate methods according to the actual situation.

[0024] The indicators involved in the following examples and their measurement methods are as follows: (1) Capsaicin concentration The concentration of capsaicin in the sample is determined by high performance liquid chromatography (HPLC). Specifically: Accurately weigh 0.2, 0.4, 0.6, 0.8 and 1.0 mg of capsaicin standard products (purity ≥ 98%), dissolve them in 1 mL of chromatographic methanol, filter through a 0.22 μm organic filter membrane, and inject them into a liquid chromatography sample vial for testing; The detection conditions of HPLC are as follows: The mobile phase is composed of chromatographic methanol and ultrapure water in a volume ratio of 78:22. Inject 20 μL of the sample into a C18 chromatographic column. At a mobile phase flow rate of 1 mL / min, detect at a UV wavelength of 280 nm for 15 min, record the peak area. Take the concentration of the capsaicin standard product as the abscissa and the peak area of the liquid chromatography as the ordinate to draw a standard curve. The equation of the obtained standard curve is: y = 5718.2x + 37.046, R 2 = 0.9996, meeting the requirements of the standard curve and can be used for the calculation of capsaicin concentration.

[0025] Weigh 1 mg of the emulsion sample, perform the detection according to the above steps, record the peak area, and calculate the concentration of capsaicin in the sample according to the standard curve.

[0026] (2) Encapsulation efficiency of capsaicin Take 1 mL of the emulsion, add 9 mL of chromatographic methanol to dissolve the unentrapped free capsaicin, centrifuge at 5880 × g for 15 min at 4 °C, collect the supernatant, and determine the capsaicin concentration in the supernatant according to the method described in (1) above to obtain the free capsaicin concentration; Take 1 mL of the emulsion, add 9 mL of chromatographic methanol, and ultrasonically disrupt it at a frequency of 40 kHz for 20 min. Determine the total capsaicin concentration in the emulsion according to the method described in (1); Calculate the encapsulation efficiency of capsaicin according to the following formula: Encapsulation efficiency of capsaicin (%) = (total capsaicin concentration - free capsaicin concentration) / total capsaicin concentration × 100.

[0027] (3) In vitro release rate of capsaicin Take 1 mL of the emulsion and add 9 mL of simulated gastric fluid. Simulate digestion at 37 °C at a rotation speed of 120 rpm for 120 min. Then take a sample, centrifuge at 5880 × g for 15 min at 4 °C, collect the supernatant, and determine the capsaicin concentration according to the method described in (1) to obtain the released capsaicin concentration; Calculate the in vitro release rate of capsaicin according to the following formula: In vitro release rate of capsaicin (%) = (CV / M) × 100; In the formula, C represents the released capsaicin concentration, V represents the volume of the supernatant, and M represents the total mass of capsaicin in the emulsion, which is determined and calculated according to the method for determining the total capsaicin concentration in the emulsion described in (2) above.

[0028] Example 1 This example is used to illustrate the effect of adding modified cellulose nanofibers on the encapsulation efficiency of capsaicin in the emulsion.

[0029] Experimental example: Preparation of an emulsion encapsulating capsaicin Subject a cellulose nanofiber solution with a mass fraction of 6% to high-pressure plasma treatment for 6.5 min under the conditions of jet discharge mode, a pressure of 190 MPa, a voltage of 9 kV, and a frequency of 50 kHz. Mix it with a chickpea protein solution with a mass fraction of 4% according to a mass ratio of 3:20, and then mix it with sunflower seed oil dissolved with capsaicin (the concentration of capsaicin is 0.0008 mol / L) according to a volume ratio of 2:9. Subsequently, homogenize it for 3 min under the conditions of a pressure of 120 MPa and a rotation speed of 12000 rpm to obtain an oil-in-water emulsion encapsulating capsaicin.

[0030] Set the following comparative examples on the basis of the above experimental example: Comparative Example 1: Without adding cellulose nanofiber solution (directly mixing chickpea protein solution with sunflower oil); Comparative Example 2: Adding unmodified cellulose nanofibers (canceling the high - voltage plasma treatment, directly mixing cellulose nanofiber solution with chickpea protein solution).

[0031] The encapsulation efficiency of capsaicin in the emulsion samples of the above experimental examples and comparative examples was tested, and the test results are shown in Table 1.

[0032] Table 1 Test results of capsaicin encapsulation efficiency of different emulsions 。

[0033] Example 2 Table 2 Test results of in vitro release rate of capsaicin from different emulsions 。

[0034] According to the test results in Table 2, it can be seen that only within the parameter range defined in the present invention for the high - voltage plasma modification of cellulose nanofibers can the in vitro release rate of capsaicin in the prepared emulsion be controlled between 10% - 20%, realizing the controllable release of capsaicin after encapsulation. Changing the pressure, voltage or frequency parameters will cause the capsaicin in the emulsion to be released too fast.

[0035] Example 3 Preparing an emulsion encapsulating capsaicin: A cellulose nanofiber solution with a mass fraction of 4.9% was subjected to high - voltage plasma treatment for 6.6 min under the conditions of jet discharge mode, a pressure of 180 MPa, a voltage of 7 kV, and a frequency of 45 kHz. After mixing with a chickpea protein solution with a mass fraction of 3.8% according to a mass ratio of 2.8:20, it was then mixed with sunflower oil dissolved with capsaicin (the concentration of capsaicin was 0.00061 mol / L) according to a volume ratio of 1.9:9. Subsequently, under the conditions of a pressure of 110 MPa and a rotation speed of 11800 rpm, it was homogenized for 2.7 min to obtain an oil - in - water emulsion encapsulating capsaicin.

[0036] It was determined that the encapsulation efficiency of this emulsion for capsaicin was 87.72%, and the in vitro release rate was 18.04%.

[0037] Example 4 Preparing an emulsion encapsulating capsaicin: A cellulose nanofiber solution with a mass fraction of 6.7% was subjected to high-voltage plasma treatment for 6.5 min under the conditions of jet discharge mode, a pressure of 168 MPa, a voltage of 8.4 kV, and a frequency of 39 kHz. It was then mixed with a chickpea protein solution with a mass fraction of 5.3% at a mass ratio of 3.5:20, and then further mixed with sunflower oil dissolved with capsaicin (the concentration of capsaicin was 0.0006 mol / L) at a volume ratio of 2.5:9. Subsequently, under the conditions of a pressure of 125 MPa and a rotation speed of 12,800 rpm, it was homogenized for 3 min to obtain an oil-in-water emulsion encapsulating capsaicin.

[0038] It was determined that the encapsulation efficiency of this emulsion for capsaicin was 90.91%, and the in vitro release rate was 17.17%.

[0039] Example 5 Preparation of an emulsion with controlled release of capsaicin: A cellulose nanofiber solution with a mass fraction of 7.5% was subjected to high-voltage plasma treatment for 7 min under the conditions of jet discharge mode, a pressure of 180 MPa, a voltage of 10 kV, and a frequency of 52 kHz. It was then mixed with a chickpea protein solution with a mass fraction of 4.5% at a mass ratio of 4.5:20, and then further mixed with sunflower oil dissolved with capsaicin (the concentration of capsaicin was 0.00085 mol / L) at a volume ratio of 3:9. Subsequently, under the conditions of a pressure of 130 MPa and a rotation speed of 13,000 rpm, it was homogenized for 3.5 min to obtain an oil-in-water emulsion encapsulating capsaicin.

[0040] It was determined that the encapsulation efficiency of this emulsion for capsaicin was 94.29%, and the in vitro release rate was 13.24%.

[0041] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing examples, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An emulsion for embedding capsaicin, characterized in that: The water phase is a plant protein-modified cellulose nanofiber solution, and the oil phase is a plant oil solution containing capsaicin.

2. The emulsion according to claim 1, characterized in that The concentration of capsaicin in the vegetable oil solution containing capsaicin is 0.0004-0.001 mol / L.

3. The emulsion according to claim 1, characterized in that The plant protein-modified cellulose nanofiber solution is obtained by mixing a modified cellulose nanofiber solution and a plant protein solution in a mass ratio of 1-5:

20.

4. The emulsion according to claim 3, characterized in that The mass fraction of the modified cellulose nanofiber solution is 4-8%.

5. The emulsion according to claim 3, characterized in that The mass fraction of the vegetable protein solution is 2-7%.

6. The emulsion according to claim 1, characterized in that The volume ratio of the water phase to the oil phase is 1-3:

9.

7. A method for preparing an emulsion for embedding capsaicin, characterized in that: The following steps are involved: The cellulose nanofiber solution is subjected to high-pressure plasma treatment to obtain a modified cellulose nanofiber solution, which is mixed with a plant protein solution to obtain an aqueous phase; dissolving capsaicin in vegetable oil to obtain an oil phase; The oil phase and the water phase are mixed and subjected to high pressure homogenization to obtain an oil-in-water emulsion.

8. The preparation method according to claim 7, characterized in that: The high-pressure plasma treatment conditions are: jet discharge mode, pressure of 150-200 MPa, voltage of 4-11 kV, frequency of 34-57 kHz, and time of 4-8 min.

9. The preparation method according to claim 7, characterized in that: The high-pressure homogenization treatment is performed at a pressure of 90-130 MPa, a rotation speed of 11000-13000 rpm, and a time of 2-4 min.