CN111803405B - Microcapsule capable of being used for essence and preparation method thereof - Google Patents

Abstract

The application discloses a microcapsule for essence and drug amorphization and a preparation method thereof; the preparation method of the microcapsule nanoemulsion for the amorphization of essence and medicines comprises the steps of preparing a composite lipid oil phase; preparing an aqueous phase from starch esterified with octenyl succinic acid; mixing the water phase and the oil phase, homogenizing under high pressure to obtain high-load high-thermal stability microcapsule nanoemulsion; the preparation of the composite lipid oil phase is to heat and stir the shea butter, the wax and the active ingredients, and melt the shea butter and the wax until the shea butter, the wax and the active ingredients are fully mixed; the microcapsule prepared by the application has good fluidity, high loading capacity and high encapsulation efficiency, has very excellent thermal stability, reduces the storage requirement and prolongs the storage life.

Description

Microcapsule capable of being used for essence and preparation method thereof

Technical Field

The application belongs to the technical field of microcapsules, and particularly relates to a microcapsule capable of being used for essence and a preparation method thereof.

Background

Volatile active compounds, of which fragrances and perfumes occupy a large group, have a wide range of applications in the cosmetic, food and pharmaceutical industries. However, volatile actives are unstable, sensitive to light, heat, oxygen and moisture, and are easily lost during processing and use due to their volatile nature, which is detrimental to transportation and storage, limiting the practical use of volatile compounds. In order to solve the problems, the active raw materials can be encapsulated in microcapsules by utilizing a microencapsulation technology, so that the effects of changing the existence state of substances, protecting sensitive components, reducing volatility, controlling release, prolonging storage time and the like are achieved.

The other active ingredients, namely the second class (poor water solubility and good permeability) and the fourth class (poor water solubility and poor permeability) of compounds in the biopharmaceutical classification system, such as curcumin, resveratrol, indomethacin, progesterone and the like, have low bioavailability of drugs due to easy crystallization and poor water solubility, and influence the administration effect. One of the important ways to increase the solubility and dissolution rate of such drugs and thus the bioavailability is to amorphize the drug by disrupting or preventing its long-range crystalline molecular order, forming an amorphous state.

The spray drying method is the most widely adopted method in the preparation method of the essence and spice microcapsule, and has the characteristics of simple operation, low cost, easy continuous production, high drying rate, good product dispersibility and solubility and the like. The conventional spray drying process steps can be described simply as: uniformly dispersing the core material in the wall material solution to prepare solution, emulsion or suspension, feeding the test solution into spray drying equipment, atomizing into liquid drops through airflow, uniformly dispersing in the airflow, and quickly evaporating the solvent for dissolving the wall material, and solidifying the wall material to form the microcapsule. There are three general categories of wall materials commonly used for spray drying: carbohydrates, hydrocolloids, proteins.

Solid lipid nanoparticles (solid lipid nanoparticles, SLN) are emulsion-type encapsulation carriers, wherein one or more high-melting solid lipids are used as carriers, active substances are encapsulated in lipid cores, and the active substances are dispersed in an aqueous solution of a surfactant to form a dispersion. Numerous studies have shown that SLN can inhibit crystallization of the active.

Menthol, also known as menthol, is the main component of essential oils of peppermint and peppermint, and is an important fragrance. Menthol has not only fresh peppermint fragrance, but also the effect of stimulating cold receptors on the skin without causing actual temperature change, thus having the functions of local itching relieving, pain relieving, cooling and slight local tingling, and being widely applied to food, medicine, toothpaste, oral hygiene products, cosmetics, cigarette production and the like. In the food industry, menthol can be used as a flavoring agent for foods such as beverages, cakes, candies, chewing gum and the like, and can increase the flavor of the foods. Can be used as irritant in medicine, acts on skin or mucosa, and has effects of refreshing and relieving itching; it can be used for treating headache, and inflammation of nose, pharynx, and larynx. Can be used for deodorizing and refreshing in toothpaste and oral hygiene products. In the cosmetic industry, the product can be used as a cooling agent, a permeation enhancer or essence and added into products in various dosage forms.

However, menthol is poor in stability, volatile (particularly, more serious in volatilization loss under high temperature conditions), easy to crystallize, poor in water solubility (0.4 mg/L), irritating to skin and eyes, affecting the use effect, and is a difficult problem to apply safely and effectively to cosmetic formulations. The volatility of menthol can be reduced through microcapsule embedding, external components are isolated, and the menthol is released in a controlled manner, so that the effects of protecting a core material, slowly releasing, lasting cooling and improving thermal stability are achieved.

The spray drying method for preparing the essence and spice microcapsule mostly adopts polymer wall materials such as modified starch, arabic gum, polyvinyl alcohol and the like, but generally has the problems of low loading, high surface oil content, poor thermal stability and the like.

Disclosure of Invention

This section is intended to outline some aspects of embodiments of the application and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the application and in the title of the application, which may not be used to limit the scope of the application.

The present application has been made in view of the above technical drawbacks.

Therefore, as one of the aspects of the present application, the present application overcomes the deficiencies of the prior art, and provides a microcapsule for essence and a preparation method thereof.

In order to solve the technical problems, the application provides the following technical scheme: a method for preparing microcapsule nanoemulsion for essence comprises preparing composite lipid oil phase; preparing an aqueous phase from starch esterified with octenyl succinic acid; mixing the water phase and the oil phase, homogenizing under high pressure, and obtaining the microcapsule nanoemulsion with high load and high thermal stability.

As a preferable scheme of the preparation method of the microcapsule nanoemulsion for essence, disclosed by the application, the preparation method comprises the following steps: the preparation of the composite lipid oil phase is to heat and stir the shea butter, the wax and the active ingredients, and melt the shea butter and the wax until the shea butter, the wax and the active ingredients are fully mixed;

as a preferable scheme of the preparation method of the microcapsule nanoemulsion for essence, disclosed by the application, the preparation method comprises the following steps: the mass ratio of the shea butter to the wax to the active ingredients is (1-7): (0-12): (3-15).

As a preferable scheme of the preparation method of the microcapsule nanoemulsion for essence, disclosed by the application, the preparation method comprises the following steps: the effective components comprise one or more of menthol, eugenol, vanillin, camphor, citronellal, eucalyptol, limonene, curcumin and resveratrol.

As a preferable scheme of the preparation method of the microcapsule nanoemulsion for essence, disclosed by the application, the preparation method comprises the following steps: the wax comprises one or more of candelilla wax, beeswax, carnauba wax, microcrystalline wax and ceresin; the octenyl succinic acid esterified starch comprises one or more of Capsul, purity Gum Ultra, HI-CAP 100;

as a preferable scheme of the preparation method of the microcapsule nanoemulsion for essence, disclosed by the application, the preparation method comprises the following steps: the homogenizing time is 0.5-3 min, and the rotating speed is 8000-15000 rpm/min; the high-pressure homogenization is performed circularly, wherein the homogenization pressure is 600-1000 bar.

As another aspect of the present application, the present application provides an application of the microcapsule nanoemulsion for essence, which can be used for one or more of lipstick, soap, talcum powder, deodorant stick, emulsion, cream, and facial mask cosmetics.

As another aspect of the present application, the present application provides a method for preparing microcapsules for essence, characterized by: spray drying the microcapsule nanoemulsion capable of being used for essence; wherein the mass ratio of the oil phase to the water phase is 0.8-1.5; the mass ratio of the effective component to the octenyl succinic acid esterified starch is (3-12): (18-27).

As a preferable scheme of the preparation method for the essence, the preparation method for the essence comprises the following steps: the spray drying is carried out, the feeding amount is 10-30 ml/min, the air inlet temperature is 160-190 ℃, and the air outlet temperature is 75-90 ℃.

As another aspect of the present application, the present application provides a microcapsule for essence, the loading of which is 15% or more.

The application has the beneficial effects that: the microcapsule prepared by the application has good fluidity, high loading capacity (more than 30%), high encapsulation efficiency (low surface menthol content (less than 1%), very excellent thermal stability, and stable performance after being stored at a high temperature for 6 months after being placed for 12 hours at a temperature of 100 ℃ and the menthol loss weight being less than 7%, thereby reducing the storage requirement and prolonging the storage life.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:

FIG. 1 is an SEM image of menthol microcapsules of each serial number in the example, and the left and right images of menthol microcapsules of each serial number are respectively detected at different times;

FIG. 2 shows the results of surface menthol content testing of each of the numbered menthol microcapsules of the examples;

FIG. 3 is a thermal stability test result of menthol microcapsules of each serial number in the examples;

FIG. 4 shows XRD test results for menthol microcapsules of each serial number and the starting material in the examples;

figure 5 is a comparison of XRD test results of menthol microcapsules prepared No. 23 after 60d, 90d and 180d placement and thermal stability after 180d placement.

Detailed Description

In order that the above-recited objects, features and advantages of the present application will become more apparent, a more particular description of the application will be rendered by reference to specific embodiments thereof.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present application is not limited to the specific embodiments disclosed below.

Further, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic can be included in at least one implementation of the application. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Surface menthol content test:

accurately weighing a certain mass m ₁ Menthol microcapsule (about 3G), 80mL of absolute ethanol was added, stirred magnetically at room temperature for 1min with gentle stirring, and the mixture was stirred with a G3 sand core funnel (m was previously weighed ₂ ) Suction filtering, washing with a small amount of absolute ethanol for 3 times, air drying the sand core funnel and filter residue in a fume hood overnight, volatilizing ethanol completely, and weighing m ₃ . The calculation formula of the menthol content on the surface is as follows:

surface menthol content= (m ₁ +m ₂ -m ₃ )/(m ₁ X load)

Menthol loading test:

accurately weighing and accurately weighing a certain mass m ₄ (about 3 g) menthol microcapsules were placed in Petri dish m ₅ 80g of deionized water and 20g of ethanol are added, and the mixture is placed in a 100 ℃ oven for drying, and the weight loss part is menthol. Repeatedly adding deionized water and ethanol (mass ratio of 4:1), and drying in oven at 100deg.C until constant weight m ₆ 。

Menthol loading= (m ₆ ﹣m ₅ )/m ₄

In an embodiment, the core material is a composite lipid and essence or medicine, such as shea butter, candelilla wax and menthol, the wall material comprises octenyl succinic acid esterified starch or silica, and the core-wall ratio is the mass ratio of the core material to the wall material.

The theoretical loading of the microcapsules refers to the mass fraction of menthol in the formulation to total solids, excluding water. Menthol is lost during the preparation process and it is therefore interesting to measure the actual loading. The influence of the preparation method on the menthol retention rate can be analyzed from the comparison of the theoretical loading and the actual loading, and if the theoretical loading and the actual loading are not different, the menthol loss is small and the retention rate is high in the preparation process.

Example 1:

dissolving Xiang Xin alkenyl succinic acid esterified starch (HI-CAP 100) in water, stirring in a constant temperature water bath at 90 ℃ for 1h, and gelatinizing the starch to form a transparent solution; heating oil phase menthol in water bath at 80deg.C to completely melt. Pouring the oil phase into the water phase, homogenizing for 1min with a homogenizer at 10000rpm/min to obtain the pre-emulsion. Homogenizing the pre-emulsion under high pressure, homogenizing under 800bar, circulating for 5 rounds to obtain hot nano emulsion, and naturally cooling to room temperature. Feeding the cooled emulsion to room temperature into a peristaltic pump for spray drying, wherein the feeding amount is 20ml/min, the air inlet temperature of spray drying is 180 ℃, the air outlet temperature is 80 ℃, and white microcapsule powder with good fluidity and average particle size of 3.25-6.23 mu m is obtained.

Table 1 menthol microcapsule formulation and results

The size of the SLN particle in the emulsion is mainly affected by the core-to-wall ratio and the homogenization conditions. In this example, the process was preferable, and the homogenization conditions were the same at the time of preparation, so that the major reason for the large difference in SLN particle size here was the difference in core-to-wall ratio, the wall material ratio was small, and the emulsification effect was poor.

The morphology of the particles obtained by spray drying depends on various factors such as drying kinetics and liquid phase composition. At the beginning of the drying process, the atomized droplet surface begins to dry, forming a shell, and then bubble nucleation occurs, the bubbles growing, expanding and bursting through the surface until most of the internal moisture evaporates. Since the drying conditions of the 4 formulations are constant, the different morphology of the dried particles is only affected by their composition. The film forming properties of the wall material, the interaction of the wall material with the active substance (menthol) and other factors affect the morphology of the solid particles. As can be seen in FIG. 1, the microcapsules are spherical and have depressions, wrinkles, irregularities, and varying sizes on the surface. This is a typical feature of low-load capsules, which become progressively filled and less wrinkled as menthol loading increases, but the microcapsules found in the No. 13 formulation break up. No. 10-13 microcapsules were free of added lipid, menthol was encapsulated with single octenyl succinic acid esterified starch, and menthol in No. 10-13 microcapsule formulation: starch is 1:9,2:8,3:7,4:6, respectively, and it can be seen that as menthol loading increases, i.e. oil: the proportion of the emulsifier is increased, the emulsification effect is reduced, the emulsion is unstable, and the emulsion is partially demulsified in the spray drying process, so that the No. 13 microcapsule is broken.

Figure 4 shows the XRD diffractogram of the starting materials in the formulation, candelilla wax crystals and menthol crystals with sharp diffraction peaks, starch without crystallization (gentle steamed bread peaks). The formulations 10, 11, 12 and 13 of example 1 were only starch and menthol without adding lipid. It can be seen from fig. 4 that menthol in microcapsules No. 10 and No. 11 was not crystallized, and menthol in microcapsules No. 12 and No. 13 was crystallized. This is because at low loadings of menthol (i.e., when the core-to-wall ratio is low), crystallization of menthol is inhibited by hydrogen bonding between the starch and menthol, and as the loading increases (the core-to-wall ratio increases), a small amount of starch is insufficient to inhibit crystallization of excess menthol.

Example 2: silica (i.e. No. 23-SiO) ₂ )

By weight, the aqueous phase: dissolving 19.2 parts of octenyl succinic acid esterified starch (HI-CAP 100) in 62.5 parts of water, stirring for 1h in a constant temperature water bath at 90 ℃, and gelatinizing the starch to form a transparent solution; an oil phase: 1.2 parts of shea butter, 3.6 parts of candelilla wax and 12 parts of menthol are stirred for 1h in a constant temperature water bath at 80 ℃ until completely melted and fully miscible. Pouring the oil phase into the water phase, homogenizing for 1min with a homogenizer at 10000rpm/min to obtain the pre-emulsion. The pre-emulsion is homogenized under high pressure at 800bar, and circulated for 5 rounds to obtain a hot nano emulsion, 1.5 parts of hydrated silica is added, and the mixture is slowly stirred to be cooled to room temperature. Feeding the cooled emulsion to room temperature into a peristaltic pump for spray drying, wherein the feeding amount is 20ml/min, the air inlet temperature of spray drying is 180 ℃, and the air outlet temperature is 80 ℃, so that off-white microcapsule powder is obtained, and the fluidity is good.

The octenyl succinic acid esterified starch (Octenyl Succinic Anhydride Modified Starch, OSA) is also called octenyl succinic acid esterified starch, is white powder, is nontoxic and odorless, can be dissolved in hot water, can be dissolved in cold water after being subjected to pregelatinization treatment, is transparent liquid, and has better stability in acid-base solution. The octenyl succinic acid esterified starch is a product obtained by taking starch derivatives (including pyrolyzed starch, acidolyzed starch, enzymatically hydrolyzed starch and the like) as raw materials and carrying out esterification reaction with octenyl succinic anhydride. Octenyl succinic esterified starch with an FDA approved degree of substitution of not more than 0.02 is useful as a food additive. The starch molecule is simultaneously introduced with hydrophilic carboxyl groups and lipophilic octenyl groups, so that the octenyl succinic acid esterified starch has hydrophilic and lipophilic amphoteric properties, and therefore has good emulsifying properties. The octenyl succinic acid esterified starch not only has good emulsion stability and high-concentration low-viscosity property, but also has good fluidity and hydrophobicity, can prevent starch particles from agglomerating, can be uniformly dispersed in emulsion, and ensures that the emulsion has good fluidity, thus being an ideal microcapsule wall material.

OSA (HI-CAP 100 and CAPs) as a microcapsule wall material has a high packing amount, can pack more menthol than a wall material such as acacia, but has a problem of high surface menthol content, and menthol whisker growth is observed on the microcapsule surface. The crystallinity of menthol leads to poor encapsulation effect and low encapsulation efficiency, and the introduction of the solid lipid nanoparticles can effectively inhibit the crystallization of menthol. Candelilla wax is also called candelilla wax, has a melting point of 66-69 ℃, is hard and brittle in texture and is not adhered. A single solid lipid (candelilla wax) encapsulates menthol, which is expelled due to the highly crystalline candelilla wax being prone to form a perfect lattice, thus requiring the addition of semi-solid shea butter to overcome this disadvantage. The mixed lipid of the shea butter and the candelilla wax can wrap menthol to form a first-stage wall material to inhibit menthol crystallization, so that the softening temperature of the core material is increased; and then the octenyl succinic acid esterified starch HI-CAP100 with emulsifying property is used as a secondary wall material for wrapping, so that the encapsulation rate of menthol can be improved, and the flowability of powder can be improved. HI-CAP100 is an emulsifier when preparing the emulsion, and the emulsion forms microcapsule wall materials after spray drying, so that the irritation of the system is reduced (no surfactant is introduced).

The silica is added into the octenyl succinic acid esterified starch wall material to improve the fluidity of microcapsule powder, and the silica is small molecular nano-sized particles, so that the gaps of the macromolecular wall material can be filled, and the wall material is more compact and has enhanced strength. The surface of the compound silica microcapsule is smoother, and the fluidity is enhanced. The microcapsules without silica (No. 23) were relatively sticky and the dispersion of the microcapsules with silica added increased, indicating that the silica can enhance the dispersion and flowability of the powder and additionally make the microcapsule surface smoother.

Example 3: the preparation process of example 2 differs significantly in that the starch is hydrated overnight prior to hydration

By weight, the aqueous phase: 19.2 parts of octenyl succinic acid esterified starch (HI-CAP 100) are dissolved in 61 parts of water, hydrated overnight (12 h) under magnetic stirring, 3 parts of silica are added and stirred for 1h under a constant temperature water bath at 90 ℃; an oil phase: 1.2 parts of shea butter, 3.6 parts of candelilla wax and 12 parts of menthol are stirred for 1h in a constant temperature water bath at 80 ℃ until completely melted and fully miscible. Pouring the oil phase into the water phase, homogenizing for 1min with a homogenizer at 10000rpm/min to obtain the pre-emulsion. The pre-emulsion is homogenized under high pressure, the homogenizing pressure is 800bar, the hot nano emulsion is obtained by 5 cycles, 3 parts of hydrated silica is added, and the mixture is slowly stirred and cooled to room temperature. Feeding the cooled emulsion to room temperature into a peristaltic pump for spray drying, wherein the feeding amount is 20ml/min, the air inlet temperature of spray drying is 180 ℃, and the air outlet temperature is 80 ℃, so that off-white microcapsule powder is obtained, and the fluidity is good.

TABLE 2 menthol microcapsule formulations and results

Note that: the raw material composition of each serial number is changed only, and the other serial numbers are not changed.

Example 4: surface active agent

By weight, the aqueous phase: 10 parts of octenyl succinic acid esterified starch (HI-CAP 100) and 5 parts of Tween-20 (or Tween-60, or Tween-80) were dissolved in 75 parts of water and stirred for 1h in a constant temperature water bath at 90 ℃; an oil phase: 0.6 part of shea butter, 1.8 parts of candelilla wax and 7.6 parts of menthol are stirred for 1h in a constant temperature water bath at 80 ℃ until complete melting and complete miscibility are achieved. Pouring the oil phase into the water phase, homogenizing for 1min with a homogenizer at 10000rpm/min to obtain the pre-emulsion. Homogenizing the pre-emulsion under high pressure, homogenizing under 800bar, circulating for 5 rounds to obtain hot nano emulsion, and naturally cooling to room temperature. Feeding the cooled emulsion to room temperature into a peristaltic pump for spray drying, wherein the feeding amount is 20ml/min, the air inlet temperature of spray drying is 180 ℃, and the air outlet temperature is 80 ℃, so that off-white microcapsule powder is obtained. The menthol has large smell, great loss, poor atomizing effect and serious wall sticking. As can be seen from the following table, the effect of compounding Tween-20/Tween-60/Tween-80 is poor, a large amount of menthol is lost in the process of preparing the microcapsule, and the actual load and the theoretical value are greatly different, probably because the Tween-20/Tween-60/Tween-80 and octenyl succinic acid esterified starch in the formula have competitive adsorption, the emulsification effect is poor, and the effect of forming the microcapsule by spray drying is affected.

Table 3 formulation and results of menthol microcapsules

Sequence number	23	30	31	32
					Shea butter	1.2	0.6	0.6	0.6
Candelilla wax	3.6	1.8	1.8	1.8
					Menthol	12	7.6	7.6	7.6
HI-CIP100	19.2	10	10	10
					Tween-60		5
Tween-80			5
					Tween-20				5
Water and its preparation method	64	75	75	75
					Theoretical loading/%	33.33	30.4	30.4	30.4
Actual loading/%	32.76	7.29	6.07	9.48
					SLN mean particle size/nm	274	160.4	96.7	132.3
Average particle diameter/nm of the powder dissolved in water	716.3	2129	350	160

In order to investigate whether the addition of a surfactant can improve the emulsification effect and reduce the SLN particle size, attempts were made to formulate the surfactant in octenyl succinic esterified starch. Several tween surfactants were tried in this example, and the microcapsule performance was found to be poor at the ratio of surfactant to octenyl succinic acid esterified starch in this example. The reason for this poor effect is probably that starch (macromolecules) and surfactant (small molecules) are competitively adsorbed, and one side is fallen off and cannot be adsorbed on the oil-water interface. Under the condition of the embodiment, the starch and the surfactant do not have synergistic effect, and the synergistic effect can be possibly realized by screening the surfactant types and determining the optimal ratio of the macromolecules to the micromolecules.

Example 5: compound lipid

As in the embodiment of No. 16 in table 5, the aqueous phase, by weight: dissolving 18 parts of octenyl succinic acid esterified starch (HI-CAP 100) in 70 parts of water, stirring for 1h in a constant temperature water bath at 90 ℃, and gelatinizing the starch to form a transparent solution; an oil phase: 1.5 parts of shea butter, 4.5 parts of candelilla wax and 6 parts of menthol are stirred for 1h in a constant temperature water bath at 80 ℃ until completely melted and fully miscible. Pouring the oil phase into the water phase, homogenizing for 1min with a homogenizer at 10000rpm/min to obtain the pre-emulsion. Homogenizing the pre-emulsion under high pressure, homogenizing under 800bar, circulating for 5 rounds to obtain hot nano emulsion, and naturally cooling to room temperature. Feeding the cooled emulsion to room temperature into a peristaltic pump for spray drying, wherein the feeding amount is 20ml/min, the air inlet temperature of spray drying is 180 ℃, and the air outlet temperature is 80 ℃, so that off-white microcapsule powder is obtained. Other serial numbers only change the composition of the raw materials, and the others are unchanged.

Table 4 formulation and results of menthol microcapsules prepared in examples

Sequence number	20	21	22	23	23-no high pressure homogenization step	24	25	26	27
										Shea butter	1.5	1	1.8	1.2	1.2	3.6	2.4	4.8	0
Candelilla wax	4.5	3	5.4	3.6	3.6	3.6	2.4	0	4.8
										Menthol	10	10	12	12	12	12	12	12	12
HI-CIP100	10	19.2	19.2	19.2	19.2	19.2	19.2	19.2	19.2
										Water and its preparation method	64.8	66.8	61.6	64	64	61.6	64	64	64
Theoretical loading/%	28.4％	30.1	31.25	33.33	33.33	31.25	33.33	33.33	33.33
										Actual loading/%	28.3	30.0	30.98	32.76	22.7	31.19	33.14	32.66	33.4
SLN mean particle size/nm	244	459	272	274	2500	213	381	204	240.6
										Average particle diameter of microcapsule/. Mu.m	4.36	7.08	7.85	8.12	11.91	5.92	5.72	11.81	8
Encapsulation efficiency/%	97	93.43	97.2	99.3	68.5	99.2	95.7	93.0	92.9
										Heat loss rate/%	8.3	17.63	11.5	6.7	63.5	6.6	13.6	14.2	12.4
Core to wall ratio	0.833	0.729	1	0.875	0.875	1	0.875	0.875	0.875
										Lipid/alcohol	0.6	0.4	0.6	0.4	0.4	0.6	0.4	0.4	0.4
Wax/total solids	0.1278	0.0904	0.141	0.1	0.1	0.094	0.067	0	0.013

No. 23 is consistent with the 23-NHPH (i.e., 23-no high pressure homogenization step), but no subsequent high pressure homogenization was performed after homogenization by the 23-NHPH homogenizer, but high pressure homogenization was also performed after ordinary homogenization of 23. The emulsion effect and the SLN particle size in the emulsion are obviously affected by high-pressure homogenization, and comparison of the SLN average particle size 274nm of No. 23 and the emulsion average particle size 2.5 mu m of 23-NHPHD in Table 4 shows that the emulsion particle size is micron-sized without high-pressure homogenization, the emulsion effect difference is large, the carrying capacity, the thermal stability and the encapsulation rate are greatly different after the emulsion is sprayed into the microcapsule, and the encapsulation effect of the 23-NHPH microcapsule is poor. This illustrates that high pressure homogenization has an important impact in the microcapsule preparation process.

Standing menthol microcapsule prepared in No. 23 for 60d, 90d and 180d at normal temperature, and performing XRD test; the menthol microcapsule No. 23 placed 180d at normal temperature was subjected to load, encapsulation efficiency and thermal stability test. The menthol microcapsule prepared initially has the loading capacity of 32.8 percent and the encapsulation rate of 99.3 percent, and as shown in figure 5, no menthol crystals appear in the menthol microcapsule after being placed for 60d, 90d and 180d, which proves that the prepared microcapsule system can inhibit menthol crystals for a long time, still keeps excellent heat stability, and the menthol microcapsule has stable performance under normal temperature storage condition and no menthol leakage.

Table 5 formulation and results of menthol microcapsules prepared in example numbers

Sequence number	14	15	16	17	18	19	20	20-1	20-2	20-3
											Shea butter	3	2	1.5	1.2	0.9	0.6	1.5	2	3	4
Candelilla wax	9	6	4.5	3.6	2.7	1.8	4.5	4	3	2
											Menthol	6	6	6	6	6	6	10	10	10	10
HI-CIP100	12	16	18	19.2	19.2	19.2	19.2	19.2	19.2	19.2
											Water and its preparation method	70	70	70	70	71.2	72.4	64.8	64.8	64.8	64.8
Theoretical loading/%	20	20	20	20	20.8	21.7	28.4	28.4	28.4	28.4
											Actual loading/%	19	20	20	20	20.8	21.7	28.3	28.00	28.39	28.48
SLN mean particle size/nm	398	322	272	256	250	283	244	298	243	255
											Average particle diameter of microcapsule/. Mu.m	6.08	4.24	6.94	6.69	9.12	8.76	4.36	5.04	4.87	4.43
Encapsulation efficiency/%	74.1	89.9	90.4	95.1	89.24	91.01	97	95.29	96.87	94.77
											Heat loss rate/%	52.4	16.9	11.5	6.6	13.7	13.87	8.3	9.42	8.1	10.8
Core to wall ratio	1.5	0.875	0.667	0.5625	0.5	0.438	0.833	0.833	0.833	0.833
											Lipid/alcohol	2	1.33	1	0.8	0.6	0.4	0.6	0.6	0.6	0.6
Wax/total solids	0.3	0.2	0.15	0.12	0.09375	0.06522	0.1278	0.114	0.085	0.057

In the application, except for 10-13 # microcapsules, lipids are added in other microcapsule formulations, the wall materials of the microcapsules have certain elasticity, and in the initial stage of drying, a large amount of water vapor is rapidly generated in the atomized and dried microcapsules, so that high internal pressure is caused, the surfaces of the microcapsules expand and then shrink, and therefore, the surfaces of the microcapsules are irregular or wrinkled. In contrast, when the formulation contains lipids as carriers for menthol, the irregular surface is reduced and the microcapsule surface is more filled due to the presence of lipids in the microcapsules, which limits further shrinkage of the microcapsule shell.

This example was further analyzed from three factors, namely core-to-wall ratio (shea butter + candelilla wax + menthol: starch), lipid to menthol ratio, shea butter to candelilla wax ratio. The core-wall ratio influences the emulsification effect and the encapsulation efficiency, and when the core-wall ratio is more than or equal to 1.5, the emulsification effect is poor, the encapsulation efficiency is low, the thermal stability is poor, and the core-wall ratio is controlled within 1, so that the emulsification effect is good. Because the core wall ratio cannot be too large, it is necessary to adjust the proportion of menthol in the core material to increase the loading. According to experimental results, it can be determined that the effect of using single lipid (shea butter or candelilla wax) is poor, and the mixed lipid has a synergistic effect, and the ratio of shea butter to candelilla wax is that: candelilla wax = 1:3,1:2,1:1, powder loading, encapsulation efficiency, thermal stability were not very different, all better, when shea butter: candelilla wax = 2:1 thermal stability is somewhat worse.

The application combines two wrapping technologies, namely Solid Lipid Nanoparticle (SLN) and microencapsulation technology, and provides a composite wall material microcapsule formed by modified starch-mixed lipid. In addition, octenyl succinic esterified starches used in the present application have attempted octenyl succinic esterified starches having different degrees of substitution by esterification such as Capsul, purity Gum Ultra and HI-CAP 100. Formulations attempting to compound the capsule and HI-CAP100 at a 1:1 ratio (Nos. 28, 29), and formulations replacing HI-CAP100 with Purity Gum Ultra (No. 33), compared to No. 23, were as follows: load: 33.76% 23, 30.73% 28, 30.57% 29, 25.81% 33; encapsulation efficiency: no. 23, 99.3%, no. 83.72%, no. 29, 88.64%, no. 33, 74.96%; the thermal stability is shown in figure 3. The effect of the number 23 is best in combination. The present application finds two parameters: (1) the high-pressure homogenization of the mixed lipid (2) has a great influence on the preparation of microcapsules. In addition, it is notable that the number 33 microcapsules were dented, wrinkled and broken for the following reasons: the modified starch used in the No. 33 microcapsule formula is Purity gum ultra, the wall material has different molecular weight and poor film forming property compared with HI-CAP100, and the water evaporation speed is high in the spray drying process, so that the capsules are sunken and wrinkled.

The technology is also suitable for other essence and substances easy to crystallize, for example, the essence comprises eugenol, vanillin, camphor, citronellal, eucalyptol, limonene and the like, and the substances easy to crystallize comprise curcumin, resveratrol and the like.

Dissolving Xiang Xin alkenyl succinic acid esterified starch (HI-CAP 100) in water, stirring in a constant temperature water bath at 90 ℃ for 1h, and gelatinizing the starch to form a transparent solution; heating oil phase shea butter, wax (one or more of beeswax, carnauba wax, microcrystalline wax and ceresin), eugenol (or one or more of vanillin, camphor, citronellal, eucalyptol, limonene, curcumin, resveratrol, etc.) in water bath at 70-90deg.C until completely melted. Pouring the oil phase into the water phase, homogenizing for 1-3 min with a homogenizer at 10000-15000 rpm/min to obtain the pre-emulsion. Homogenizing the pre-emulsion under high pressure, homogenizing under 600-1000 bar, circulating for 5 rounds to obtain hot nano emulsion, and naturally cooling to room temperature. Feeding the cooled emulsion to room temperature into a peristaltic pump for spray drying, wherein the feeding amount is 15-30 ml/min, the air inlet temperature of spray drying is 160-180 ℃, and the air outlet temperature is 65-90 ℃, thus obtaining microcapsule powder.

In the optimization process of the application, the method is carried out from the following aspects: core wall ratio (0.87:1, 0.67:1,0.5:1, 0.4:1), ratio of mixed lipids (oil: wax=8:2, 7:3,5:5, 4:6), ratio of lipids to actives (0.4,0.6,0.8), spray drying parameters: spray drying inlet air temperature 160,170,180 ℃. When the core wall ratio=0.67:1, the ratio of lipids (oil: wax=7:3) was mixed, lipids: active = 0.6. Pouring the oil phase into the water phase, homogenizing for 1.5min at 12000rpm/min by a homogenizer to obtain the pre-emulsion. Homogenizing the pre-emulsion under high pressure, homogenizing under 800bar, circulating for 5 rounds to obtain hot nano emulsion, and naturally cooling to room temperature. Feeding the cooled emulsion to room temperature into a peristaltic pump for spray drying, wherein the feeding amount is 20ml/min, the air inlet temperature of spray drying is 160 ℃, and the air outlet temperature is 70 ℃, so as to obtain microcapsule powder. The microcapsule powder encapsulation efficiency and heat loss performance are good.

It should be noted that the above embodiments are only for illustrating the technical solution of the present application and not for limiting the same, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present application may be modified or substituted without departing from the spirit and scope of the technical solution of the present application, which is intended to be covered in the scope of the claims of the present application.

Claims (5)

1. A preparation method of microcapsule nanoemulsion for essence is characterized by comprising the following steps: comprising the steps of (a) a step of,

preparing a composite lipid oil phase, heating and stirring shea butter, wax and active ingredients, and melting until the shea butter, the wax and the active ingredients are fully mixed, wherein the mass ratio of shea butter to the wax to the active ingredients is 1-7: 0-12: 3-15; the ratio of the shea butter to the wax is 1:3,1:2 or 1:1; the wax is candelilla wax; the effective component is menthol;

preparing an aqueous phase from starch esterified with octenyl succinic acid;

mixing the water phase and the oil phase, wherein the mass ratio of the oil phase to the water phase is 0.8-1.5, and the mass ratio of the effective component to the octenyl succinic acid esterified starch is 3-12: 18-27, namely, homogenizing the mixture at a high pressure after homogenizing, wherein the proportion of the sum of the dosages of the three components of the shea butter, the candelilla wax and the menthol to the octenyl succinic acid esterified starch is less than 1, so as to obtain the microcapsule nano emulsion with high load and high thermal stability;

wherein the octenyl succinic acid esterified starch comprises one or more of Capsul, purity Gum Ultra, HI-CAP 100.

2. The method for preparing the microcapsule nanoemulsion for essence according to claim 1, wherein the method comprises the following steps: the homogenizing time is 0.5-3 min, and the rotating speed is 8000-15000 rpm/min; and the high-pressure homogenization is performed circularly, wherein the homogenization pressure is 600-1000 bar.

3. A preparation method of microcapsules for essence is characterized in that: spray drying the microcapsule nanoemulsion for essence prepared by the method of claim 1 or 2.

4. A process for the preparation of microcapsules useful in fragrances as claimed in claim 3, characterized in that: the spray drying is carried out, the feeding amount is 10-30 ml/min, the air inlet temperature is 160-190 ℃, and the air outlet temperature is 75-90 ℃.

5. Use of the microcapsule nanoemulsion used for essence according to any one of claims 1-4, characterized in that: can be used for preparing one or more cosmetics selected from lipstick, soap, talcum powder, deodorant stick, lotion, cream, and facial mask.