Tea oil microcapsule with double-layer core-shell structure and preparation method and application thereof

Abstract

The present invention belongs to the technical field of biomaterial preparation, and specifically relates to a tea oil microcapsule with a double-layer core-shell structure, and a preparation method and application thereof. The present invention provides an oil body cell emulsion, which is composed of oil body cells and a camellia oleifera extract solution; and based on this, a tea oil microcapsule is further provided, which uses fat-soluble components as the core layer, the oil body cell emulsion as the first shell layer of the fat-soluble components, and the protein or polysaccharide added later as the second shell layer to form a double-layer core-shell structure; the tea oil microcapsule has the advantages of controllable size, high fat-soluble component embedding rate and good storage stability; and the preparation process of the tea oil microcapsule is simple to operate, the reaction conditions are mild, and no curing agent or surfactant is added, which is green and safe, and has great application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomaterial preparation, and more specifically, relates to a tea oil microcapsule with a double-layer core-shell structure and a preparation method and application thereof. Background Art

[0002] As a new carrier technology, microcapsules have shown good application prospects in the fields of medicine, food, cosmetics, etc. The microencapsulation technology has overcome many application shortcomings and limitations of fat-soluble functional ingredients that are sensitive to the outside world, and expanded their application scope. There are many methods of microencapsulation, mainly including extrusion, spray drying, supercritical fluid, air suspension and complex coacervation. Among them, complex coacervation, as an emerging technology, has the characteristics of high safety, mild reaction conditions, high encapsulation efficiency and good controlled release. At present, complex coacervation is one of the most commonly used microencapsulation methods for encapsulating hydrophobic functional ingredients, such as the encapsulation of important nutrients such as vitamin E. However, this method requires the additional addition of a curing agent as a cross-linking agent or surfactant to improve the stability of the system. Aldehyde curing agents are usually used, but the residual chemical cross-linking agent and the biodegradation of chemical cross-linked macromolecules in the body are toxic, which seriously limits the application of the product.

[0003] In order to solve the above problems, some researchers have improved the application technology of complex coacervation microencapsulation method in vitamin E microcapsules. For example, Feng Yan (Feng Yan. Research on the preparation of vitamin E microcapsules by complex coacervation method [D]. Jiangnan University, 2008.) disclosed the preparation of vitamin E microcapsules by complex coacervation method using glutamine transaminase as a curing agent and gelatin and gum arabic as wall materials; Qiang Junfeng (Qiang Junfeng. Effect of wall material ratio on the preparation of vitamin E microcapsules by complex coacervation method) E Influence of microcapsule embedding effect [J]. Food and Machinery, 2017, 33(02): 175-178. DOI: 10.13652 / j.issn.1003-5788.2017.02.037.) disclosed that a natural vitamin E microcapsule with an average particle size of 35.17 μm was prepared by composite coacervation method using gelatin and sodium alginate as wall materials and 5% calcium chloride solution as curing agent, and the embedding rate of vitamin E was as high as 74.7%. However, even if a non-toxic curing agent or surfactant is used, there is still a problem of high cost of use. Using glutamine aminotransferase as a curing agent also has the disadvantages of long reaction time and heating.

[0004] With the development of economy and society, people are paying more and more attention to the safety, non-toxicity and environmental protection of microcapsule raw materials. Therefore, it is of great significance to develop new microcapsules that are safe and non-toxic, do not require additional curing agents or surfactants, are low-cost and can improve the stability of active ingredients. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of the existing microcapsule technology, which requires the additional addition of a curing agent or a surfactant, the potential safety hazards of toxic curing agents, and the high use costs of non-toxic curing agents or surface emulsifiers, such as long reaction time and the need for heating, and to provide an oil body cell emulsion.

[0006] The purpose of the present invention is to provide a green and safe tea oil microcapsule with a double-layer core-shell structure.

[0007] The purpose of the present invention is to provide a method for preparing the tea oil microcapsules.

[0008] Another object of the present invention is to provide the use of the oil body cell emulsion or the tea oil microcapsule in the preparation of medicines, foods or cosmetics.

[0009] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0010] An oil body cell emulsion, consisting of oil body cells and a camellia oleifera extract solution;

[0011] The mass volume ratio of the oil body cells and the camellia oleifera extract solution is 2.5-7.5:50 g / mL;

[0012] The method for preparing oil body cells comprises the following steps: adding a buffer solution into oil tea seeds, adjusting pH, adding plant complex enzymes for enzymolysis, inactivating enzymes, breaking the wall, filtering, centrifuging, and taking the upper layer to obtain the oil body cells.

[0013] Oil body cells are a natural emulsifier and natural water-in-oil emulsion. They are rich in triglycerides and a small amount of polar lipids. They are embedded in specific phospholipid membranes and proteins. As a natural product, the advantages of oil body cells meet the needs of consumers, such as no emulsification process, simple and environmentally friendly extraction, safety and rich nutrition.

[0014] Furthermore, the camellia seeds are fresh or dried camellia seeds.

[0015] Furthermore, the oil body cells were tested and found to be mainly composed of the following components in parts by weight: 0.3 to 3 parts of protein, 0.6 to 1.5 parts of phospholipids, 76 to 85 parts of oil and 10 to 20 parts of water.

[0016] Furthermore, the protein includes oleosin, caleosin and steroleosin.

[0017] Furthermore, the camellia oleifera extract solution is obtained by extracting camellia oleifera with water.

[0018] Specifically, the preparation method of the camellia oleifera extract solution is as follows: weigh the dried and crushed camellia oleifera raw material, add water at a solid-liquid ratio of 1:15-30 (g / mL), extract at 40-80°C for 20-60 minutes, and filter to obtain the camellia oleifera extract solution.

[0019] More specifically, the preparation method of the camellia oleifera extract solution is as follows: weigh the dried and crushed camellia oleifera raw material, add water at a solid-liquid ratio of 1:20 (g / mL), extract at 69° C. for 52 minutes, and filter to obtain the camellia oleifera extract solution.

[0020] Preferably, the camellia oil flower is selected from the flowers of common white-flowered camellia oil or red-flowered camellia oil.

[0021] Furthermore, the oil-tea camellia extract solution was tested, and it was found that the oil-tea camellia extract solution was mainly composed of the following components: 30-40 mg / g protein, 5-7 mg / g crude fat, 2-3.5 mg / g amino acids, 200-280 mg / g total sugar, 40-50 mg / g polyphenols, 170-230 mg / g flavonoids and 30-50 mg / g caffeine. The main components of the extract solutions of different varieties of oil-tea camellia are slightly different.

[0022] Furthermore, the plant complex enzyme is cellulose enzyme, hemicellulase, β-glucanase and pectinase.

[0023] Preferably, the mass ratio of the cellulase, hemicellulase, β-glucanase and pectinase is 1-3:0-1:1-2:1-2.

[0024] Preferably, the mass volume ratio of the camellia seeds to the buffer solution is 1:(4-10) g / mL.

[0025] Preferably, the pH is 4.5-9.

[0026] Preferably, the buffer solution is a phosphate buffer.

[0027] More preferably, the concentration of the phosphate buffer solution is 0.1-0.5 mol / L.

[0028] Preferably, the added amount of the plant complex enzyme is 1% to 6%.

[0029] Preferably, the amount of the plant complex enzyme added is 3%. Although increasing the amount of enzyme added will increase the contact area between the enzyme and the substrate, thereby fully destroying the cell wall of the oil tea seed and releasing more oil body cells, adding excessive enzymes will destroy the integrity of the oil body cells, thereby reducing the yield of the oil body cells and being unfavorable for the subsequent embedding of fat-soluble components. Therefore, the preferred amount of the plant complex enzyme added is 3%.

[0030] Preferably, the enzymatic hydrolysis time is 0.5 to 3 hours.

[0031] More preferably, the enzymolysis time is 1 hour. Since too long an enzymolysis time may cause the oil body cells in the system to aggregate and make the system unstable, the preferred degradation time is 1 hour.

[0032] Preferably, the wall-breaking conditions are: 18000-23000 r / min, 30-90 s. Under such wall-breaking conditions, the tea seeds are broken, and the oil body cells are fully released without destroying their structure.

[0033] Preferably, the centrifugal condition is 8500-12000 r / min for 20-30 min. Under this centrifugal condition, the oil body cells can be well separated, while when a lower speed is used, the oil body cells cannot be well separated and are easily dissolved in the buffer solution again.

[0034] The present application provides a tea oil microcapsule with a double-layer core-shell structure, wherein the tea oil microcapsule is sequentially arranged from the inside to the outside as a core layer, a first shell layer, and a second shell layer;

[0035] The core layer is a fat-soluble component; the first shell layer is made of the oil body cell emulsion; and the second shell layer is mainly made of protein or polysaccharide.

[0036] The present invention is the first to use the oil body cell emulsion formed by the oil body cells and the camellia oleifera extract solution as the first shell solution of the fat-soluble component to prepare tea oil microcapsules, without the need to add additional curing agents or surfactants, which can not only meet the requirements of safety and environmental protection, but also improve the stability of the system. When the camellia oleifera extract solution is replaced with an equal amount of water, the embedding rate of the core material of the obtained tea oil microcapsules becomes lower, and its storage stability is also significantly reduced. This may be because the camellia oleifera extract solution contains a variety of active substances, among which the active substances interact with the oil body cells through covalent or non-covalent interactions, play the role of antioxidants and stabilizers, and improve the stability of the microcapsule system, thereby improving the embedding rate and storage stability of the core material.

[0037] The present invention also provides a method for preparing the tea oil microcapsules, comprising the following steps:

[0038] S1. The oil body cells and the camellia oleifera extract solution are thoroughly mixed to form an oil body cell emulsion;

[0039] S2. adding the fat-soluble component to the oil body cell emulsion obtained in step S1, and mixing thoroughly to obtain a mixed solution;

[0040] S3. Add the protein or polysaccharide solution into the mixed solution obtained in step S2, mix thoroughly, and adjust the pH to obtain tea oil microcapsules.

[0041] The preparation method of the present application is simple and environmentally friendly. It does not require the addition of additional curing agents or surfactants, nor does it require heating. A stable microcapsule system can be obtained in a relatively short time. The oil body cells and the camellia oleifera extract solution are fully mixed to form an oil body cell emulsion as the first shell layer solution of the fat-soluble components. The protein or polysaccharide added later is used as the second shell layer raw material. The pH of the system is then adjusted using an acidic or alkaline reagent to make the net charge of the protein on the surface of the oil body cell emulsion positive or negative, and the protein interacts covalently, non-covalently or electrostatically with the second shell layer solution to form a double-layer core-shell structure, thereby achieving reinforced coating, strengthening the protection of the fat-soluble components, and improving the encapsulation rate and storage stability of the fat-soluble components.

[0042] Preferably, the fat-soluble components are 20% to 40% (g / mL) based on the volume of the camellia oleifera extract solution.

[0043] Preferably, the final concentration of the solution made of the second shell material in the tea oil microcapsule is 0.3wt% to 2wt%. Excessive addition of the second shell material will cause oil body cell flocculation, reduce the stability of the oil body cell emulsion, and thus lead to poor embedding effect.

[0044] Preferably, in step S3, after the protein or polysaccharide is made into a solution, the pH of the solution needs to be adjusted to be consistent with the pH of the oil body cell emulsion obtained in step S1, and then added to the mixed solution obtained in step S2, so that the two can be mixed more evenly.

[0045] Preferably, in step S1, the speed of the thorough mixing is 300-1000 r / min. Under this condition, the oil body cells can be better mixed with the Camellia oleifera extract solution to obtain a uniform oil body cell emulsion without destroying the structure of the oil body cells.

[0046] Preferably, in step S1, the time for sufficient mixing is 10 to 30 minutes.

[0047] Preferably, in step S2, the speed of the sufficient mixing is 30000-80000 r / min. Under this condition, the structure of the oil body cells is destroyed, so that the fat-soluble components can enter the interior of the oil body cells.

[0048] Preferably, in step S2, the time for sufficient mixing is 1 to 5 minutes.

[0049] Preferably, the protein is gelatin or whey protein.

[0050] The polysaccharide is an anionic polysaccharide or a cationic polysaccharide.

[0051] Preferably, the anionic polysaccharide is any one of pectin, gum arabic, sodium alginate, carrageenan and xanthan gum.

[0052] Preferably, the anionic polysaccharide is pectin or gum arabic.

[0053] More preferably, the anionic polysaccharide is pectin.

[0054] Preferably, the cationic polysaccharide is chitosan and its derivatives.

[0055] More preferably, the cationic polysaccharide is chitosan quaternary ammonium salt.

[0056] Preferably, the fat-soluble component is vitamin E, β-carotene, astaxanthin, D-limonene, resveratrol or linolenic acid.

[0057] More preferably, the fat-soluble component is vitamin E.

[0058] More preferably, the vitamin E component is 30% to 40% (measured as a percentage of the volume of the camellia oleifera extract solution). When the vitamin E content is equal to or greater than 50%, the size of the microcapsules is uneven, and the microcapsules are aggregated and leak oil; when the fat-soluble component content is 30% to 40%, the emulsification is sufficient, the microcapsules are evenly distributed in size, and there is less oil that is not embedded and attached to the surface of the microcapsules, which has a higher embedding rate; when the vitamin E content is less than 20%, the volume of the oil body cell emulsion accounts for a large proportion, so that the microcapsule wall formed is thicker, thereby reducing the content of embedded vitamin E, so the preferred fat-soluble component content is 30% to 40%.

[0059] The present invention also provides application of the oil body cell emulsion or the tea oil microcapsule in the preparation of medicines, foods or cosmetics.

[0060] Preferably, the cosmetic is a skin care lotion.

[0061] Preferably, the skin care lotion comprises the tea oil microcapsules and a moisturizer.

[0062] Preferably, the moisturizer is glycerin or sodium hyaluronate.

[0063] The present invention has the following beneficial effects:

[0064] (1) The present invention provides an oil body cell emulsion, which is composed of oil body cells and a camellia oleifera extract solution and can be used for embedding fat-soluble components.

[0065] (2) The present invention also provides a tea oil microcapsule, which uses oil body cell emulsion as the first shell layer of the fat-soluble component and subsequently adds protein or polysaccharide as the second shell layer to form a double-layer core-shell structure; the tea oil microcapsule has the advantages of controllable size, high fat-soluble component encapsulation rate and good storage stability.

[0066] (3) The preparation method of the present invention is universal and can be used to prepare different functional microcapsules according to different application directions. The preparation process is simple to operate and the reaction conditions are mild, which is suitable for industrial production. No curing agent or surfactant is added, which is green and safe and has great application value. DETAILED DESCRIPTION

[0067] The present invention is further described below using specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0068] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0069] The method for preparing the camellia oleifera extract solution comprises the following steps:

[0070] Accurately weigh 5 g of dried and crushed Camellia oleifera raw material into a conical flask, add distilled water at a solid-liquid ratio of 1:20 (g / mL), extract at 69° C. for 52 min, and filter to obtain the Camellia oleifera extract solution.

[0071] Example 1 A method for preparing tea oil microcapsules

[0072] A method for preparing tea oil microcapsules comprises the following steps:

[0073] S1. Take 40g of camellia seeds and add them into 240mL of phosphate buffer with a pH of 6.8, add 3% of plant complex enzyme (composed of cellulase, hemicellulase, β-glucanase and pectinase), and break the cell wall after enzymolysis for 1h. After filtering with filter cloth, centrifuge at 9000r / min and take the upper layer to obtain oil body cells.

[0074] S2. Take 5 g of oil body cells, dissolve them in 50 mL of Camellia oleifera extract solution, and stir them at 800 r / min with a magnetic stirrer for 20 min to obtain an oil body cell emulsion as the first shell layer solution.

[0075] S3. Take 20 g of vitamin E oil as the nuclear layer, add it to the oil body cell emulsion obtained in step S2, and use a high-speed homogenizer to homogenize at 60,000 r / min for 2 minutes to obtain a mixed solution.

[0076] S4. Adjust the pH of the 0.6 wt% pectin solution to be consistent with the pH of the oil body cell emulsion obtained in step S2.

[0077] S5. Add 50 mL of the pectin solution obtained in step S4 to the mixed solution obtained in step S3 as the second shell solution, stir and mix, use 0.1 mol / L NaOH or 0.1 mol / L HCl to adjust the pH of the emulsion system to 3, adjust the speed to 800 r / min for electrostatic complexation, and stir for 35 minutes to obtain tea oil microcapsules.

[0078] Example 2 A method for preparing tea oil microcapsules

[0079] A method for preparing tea oil microcapsules comprises the following steps:

[0080] S1. Take 40g of camellia seeds and add them into 160mL of phosphate buffer with a pH of 5.0, add 1% of plant complex enzyme (composed of cellulase, hemicellulase, β-glucanase and pectinase), and perform enzymatic hydrolysis for 30 minutes to break the cell wall. After filtering with filter cloth, centrifuge at 9000r / min and take the upper layer to obtain oil body cells.

[0081] S2. Take 2.5 g of oil body cells, dissolve them in 50 mL of Camellia oleifera extract solution, and stir them at 600 r / min with a magnetic stirrer for 30 min to obtain an oil body cell emulsion as the first shell layer solution.

[0082] S3. Take 10 g of vitamin E oil as the nuclear layer, add it to the oil body cell emulsion obtained in step S2, and use a high-speed homogenizer to homogenize at 40,000 r / min for 4 minutes to obtain a mixed solution.

[0083] S4. Adjust the pH of the 0.3 wt% gum arabic solution to be consistent with the pH of the oil body cell emulsion obtained in step S2.

[0084] S5. Add 50 mL of the gum arabic solution obtained in step S4 to the mixed solution obtained in step S3 as the second shell solution, stir and mix, use 0.1 mol / L NaOH or 0.1 mol / L HCl to adjust the pH of the emulsion system to 4, adjust the speed to 600 r / min for electrostatic complexation, and stir for 50 minutes to obtain tea oil microcapsules.

[0085] Example 3 A method for preparing tea oil microcapsules

[0086] A method for preparing tea oil microcapsules comprises the following steps:

[0087] S1. Take 40g of camellia seeds and add them into 280mL of phosphate buffer with a pH of 8.0, add 6% of plant complex enzyme (composed of cellulase, hemicellulase, β-glucanase and pectinase), and break the cell wall after enzymolysis for 1.5h. After filtering with filter cloth, centrifuge at 9000r / min and take the upper layer to obtain oil body cells.

[0088] S2. Take 7.5 g of oil body cells, dissolve them in 50 mL of Camellia oleifera extract solution, and stir them at 1000 r / min for 10 min using a magnetic stirrer to obtain an oil body cell emulsion as the first shell layer solution.

[0089] S3. Take 20 g of vitamin E oil as the nuclear layer, add it to the oil body cell emulsion obtained in step S2, and use a high-speed homogenizer to homogenize at 80,000 r / min for 1 min to obtain a mixed solution.

[0090] S4. Adjust the pH of the 0.3 wt% chitosan quaternary ammonium salt solution to be consistent with the pH of the oil body cell emulsion obtained in step S2.

[0091] S5. Add 50 mL of the chitosan quaternary ammonium salt solution obtained in step S4 to the mixed solution obtained in step S3 as the second shell solution, stir and mix, use 0.1 mol / L NaOH or 0.1 mol / L HCl to adjust the pH of the emulsion system to 8, adjust the speed to 600 r / min for electrostatic complexation, and stir for 50 min to obtain tea oil microcapsules.

[0092] Embodiment 4-5 A method for preparing tea oil microcapsules

[0093] The difference between Example 4 and Example 1 is that the oil body cells weighed in step S2 are 2.5 g.

[0094] The difference between Example 5 and Example 1 is that the oil body cells weighed in step S2 are 7.5 g.

[0095] Other parameters and operations are referred to Example 1.

[0096] Embodiment 6-9 A method for preparing tea oil microcapsules

[0097] The difference between Example 6 and Example 1 is that the pectin concentration in step S4 is 0.3 wt %.

[0098] The difference between Example 7 and Example 1 is that the pectin concentration in step S4 is 0.6 wt %.

[0099] The difference between Example 8 and Example 1 is that the pectin concentration in step S4 is 1.5 wt %.

[0100] The difference between Example 9 and Example 1 is that the pectin concentration in step S4 is 2 wt %.

[0101] Other parameters and operations are referred to Example 1.

[0102] Embodiment 10-11 A method for preparing tea oil microcapsules

[0103] The difference between Example 10 and Example 1 is that the vitamin E oil weighed in step S3 is 10 g.

[0104] The difference between Example 11 and Example 1 is that the vitamin E oil weighed in step S3 is 15 g.

[0105] Other parameters and operations are referred to Example 1.

[0106] Embodiment 12-14 A method for preparing tea oil microcapsules

[0107] The difference between Example 12 and Example 1 is that the pH of the emulsion system is adjusted to 4 in step S5.

[0108] The difference between Example 13 and Example 1 is that the pH of the emulsion system is adjusted to 5 in step S5.

[0109] The difference between Example 14 and Example 1 is that the pH of the emulsion system is adjusted to 6 in step S5.

[0110] Other parameters and operations are referred to Example 1.

[0111] Example 15 Preparation method of tea oil skin care lotion

[0112] The tea oil microcapsules obtained in Example 1 were mixed with 5 mL of pre-emulsified sodium hyaluronate and 5 mL of water, and homogenized at a speed of 30,000 r / min for 2.5 min using a high-speed homogenizer. The pH was adjusted to 4 to obtain a tea oil skin care lotion.

[0113] Example 16 Preparation method of tea oil skin care lotion

[0114] The tea oil microcapsules obtained in Example 2 were mixed with 3 mL of pre-emulsified glycerol and 9 mL of water, and homogenized at a homogenization speed of 30,000 r / min for 2.5 min using a high-speed homogenizer. The pH was adjusted to 4 to obtain a tea oil skin care lotion.

[0115] Example 17 Preparation method of tea oil skin care lotion

[0116] The tea oil microcapsules obtained in Example 3 were mixed with 5 mL of pre-emulsified sodium hyaluronate and 5 mL of water, and homogenized for 2 min at a homogenization speed of 40,000 r / min using a high-speed homogenizer. The pH was adjusted to 8 to obtain a tea oil skin care lotion.

[0117] Comparative Examples 1 to 9 A method for preparing tea oil microcapsules

[0118] The difference between Comparative Example 1 and Example 1 is that the camellia oleifera extract solution in step S2 is replaced by an equal amount of distilled water.

[0119] The difference between Comparative Example 2 and Example 1 is that the oil body cells weighed in step S2 are 10 g.

[0120] The difference between Comparative Example 3 and Example 1 is that the vitamin E oil weighed in step S3 is 25 g.

[0121] The difference between Comparative Example 4 and Example 1 is that the pH of the emulsion system is adjusted to 2 in step S5.

[0122] The difference between Comparative Example 5 and Example 1 is that the pH of the emulsion system is adjusted to 7 in step S5.

[0123] The difference between Comparative Example 6 and Example 1 is that the pH of the emulsion system is adjusted to 8 in step S5.

[0124] The difference between Comparative Example 7 and Example 1 is that the oil body cells weighed in step S2 are replaced by Tween 80.

[0125] Other parameters and operations are referred to Example 1.

[0126] The difference between Comparative Example 8 and Example 2 is that the oil body cells weighed in step S2 are replaced by Tween 80.

[0127] Other parameters and operations are referred to Example 2.

[0128] The difference between Comparative Example 9 and Example 3 is that the oil body cells weighed in step S2 are replaced by Tween 80.

[0129] Other parameters and operations are referred to Example 3.

[0130] Comparative Example 10: A method for preparing a moisturizing skin care lotion

[0131] The tea oil microcapsules obtained in Comparative Example 7 were mixed with 5 mL of pre-emulsified sodium hyaluronate and 5 mL of water, and homogenized at a speed of 30,000 r / min for 2.5 min using a high-speed homogenizer, and the pH was adjusted to 4 to obtain a moisturizing skin care lotion.

[0132] Comparative Example 11: A method for preparing a moisturizing skin care lotion

[0133] The tea oil microcapsules obtained in Comparative Example 8 were mixed with 3 mL of pre-emulsified glycerol and 9 mL of water, and homogenized at a homogenization speed of 30,000 r / min for 2.5 min using a high-speed homogenizer, and the pH was adjusted to 4 to obtain a moisturizing skin care lotion.

[0134] Comparative Example 12: A method for preparing a moisturizing skin care lotion

[0135] The tea oil microcapsules obtained in Comparative Example 9 were mixed with 5 mL of pre-emulsified sodium hyaluronate and 5 mL of water, and homogenized for 2 min at a homogenization speed of 40,000 r / min using a high-speed homogenizer, and the pH was adjusted to 8 to obtain a moisturizing skin care lotion.

[0136] Experimental Example 1 Determination of particle size, potential, embedding rate or retention rate

[0137] (1) Determination of the electrical potential of oil body cells

[0138] The potential of the oil body cells obtained in Example 1 was measured, and the results are shown in Table 1. The isoelectric point of the oil body cells is between 4.0 and 5.0. When the pH is within this range, the surface charge of the oil body cells is close to zero, the surface charge of the droplets is reduced and the electrostatic interaction between the droplets is weakened, the oil body cells are easy to aggregate and merge, and vitamin E cannot be normally embedded. When the pH is lower than the isoelectric point of the oil body cells, the surface of the oil body cells is positively charged, and it is easy to undergo a complex coagulation reaction with negatively charged polysaccharides to achieve electrostatic coating, and obtain tea oil microcapsules with a double-layer core-shell structure; when the pH is between 5.0 and 6.0, it is slightly higher than the isoelectric point of the oil body cells. At this time, the oil body cells are weakly negatively charged and can still combine with negatively charged polysaccharides; when the pH is much higher than the isoelectric point of the oil body cells, the surface of the oil body cells is negatively charged, and it is easy to undergo a complex coagulation reaction with positively charged polysaccharides to achieve electrostatic coating, and obtain tea oil microcapsules with a double-layer core-shell structure.

[0139] Table 1 Potentials of oil body cells at different pH

[0140] pH Potential / mV 2 10.6 3 4.8 4 2.5 5 -5.4 6 -9.9 7 -15.4 8 -18.7 9 -21.3

[0141] (2) Comparison of tea oil microcapsule encapsulation effects using Tween 80 and oil body cells

[0142] The particle size, vitamin E embedding rate and vitamin E retention rate after storage for a period of time of the tea oil microcapsules obtained in Examples 1 to 3 and Comparative Examples 7 to 9 were measured. The results are shown in Table 2. When Tween 80 was used to replace oil body cells to prepare tea oil microcapsules, Tween 80 was an emulsifier and could not be used as a wall material to embed vitamin E. Therefore, the obtained microcapsules did not have a double-layer core-shell structure. Although the microcapsules were all in a uniform emulsion state, the embedding rate of vitamin E was significantly reduced. After storage at 25°C for 15 days, the retention rate of vitamin E was also significantly worse than that of the tea oil microcapsules prepared in the corresponding examples. This shows that oil body cells have excellent emulsifying properties, and uniform and stable tea oil microcapsules can be prepared without the addition of emulsifiers or curing agents. The special structure of oil body cells can be used as the first shell component of vitamin E to form a single-layer core-shell structure, and then electrostatically complexed with the polysaccharide added later to form tea oil microcapsules with a double-layer core-shell structure, which significantly improves the embedding rate of vitamin E and improves its storage stability.

[0143] Table 2 Comparison of the embedding effects of tea oil microcapsules using Tween 80 and oil somatic cells

[0144]

[0145] Table 2: The experimental data was analyzed for significance using SPSS software, and the statistical difference (P - value) was calculated using an independent - samples T - test; among them, P > 0.05 indicates no significant difference; 0.01 < P < 0.05 indicates a significant difference; P < 0.01 indicates a highly significant difference.

[0146] (3) Comparison of the embedding effects of tea oil microcapsules using distilled water and oil - camellia flower extract solution

[0147] Compare the particle size, vitamin E embedding rate, and the retention rate of vitamin E after storage for a period of time of the tea oil microcapsules obtained in Example 1 and Comparative Example 1. The results are shown in Table 3. When directly dissolving oil somatic cells with distilled water, the particle size of the obtained microcapsules is about 2.2 μm; when adding oil - camellia flower extract solution to the oil somatic cells, the particle size of the obtained tea oil microcapsules increases slightly, but the tea oil microcapsules prepared using the oil - camellia flower extract solution have a better protective effect on vitamin E. Both the embedding rate and the retention rate after storage for a certain period are significantly higher than those of the tea oil microcapsules prepared with distilled water. This shows that the active substances in the oil - camellia flower extract solution interact with the oil somatic cells through covalent or non - covalent interactions, acting as antioxidants and stabilizers, making the tea oil microcapsule system more stable, thereby extending the product shelf life.

[0148] Table 3 Comparison of the effects of dissolving oil bodies with distilled water and oil - camellia flower extract solution to prepare microcapsules

[0149] Group Particle size / μm <![CDATA[V E Embedding rate / %]]> <![CDATA[V retention rate / % after 7 days of storage at 25℃ E > Example 1 2.48 94.5 85.9 Comparative Example 1 2.20 81.9(P<0.01) 65.7(P<0.01)

[0150] Table 3: The experimental data was analyzed for significance using SPSS software, and the statistical difference (P - value) was calculated using an independent - samples T - test; among them, P > 0.05 indicates no significant difference; 0.01 < P < 0.05 indicates a significant difference; P < 0.01 indicates a highly significant difference.

[0151] (4) Influence of different oil somatic cell concentrations on the embedding effect of vitamin E

[0152] The particle size and vitamin E embedding rate of the tea oil microcapsules obtained in Examples 1, 4, 5 and Comparative Example 3 were measured. The results are shown in Table 4. When the oil body cell content is lower than 5%, the surface charge of the oil body cells cannot exert sufficient electrostatic repulsion to keep the emulsion stable. Therefore, more than 5% of oil body cells are selected for embedding vitamin E. When the oil body cell content is too high, the amphiphilic substances on the surface of the oil body cells, such as proteins and phospholipids, are fully covered on the surface of the oil droplets during the homogenization process. These amphiphilic substances strengthen the electrostatic repulsion and weaken the van der Waals attraction between the particles, resulting in an inhomogeneous emulsion system. This indicates that too high a concentration of oil body cells will also lead to an unstable emulsion system. Therefore, an oil body cell content of less than 20% is preferred.

[0153] Table 4 Effect of oil body cell concentration on vitamin E encapsulation effect

[0154] Group Oil body cell concentration / % <![CDATA[V E Embedding rate / %]]> Emulsion state Example 4 5 82.3 Uniform and stable Example 1 10 94.5 Uniform and stable Example 5 15 80.7 Uniform and stable Comparative Example 2 20 75.4 Minor oil leakage and flocculation

[0155] Table 4: Oil body cell concentration as a percentage of the volume of Camellia oleifera extract solution.

[0156] (5) Effect of pectin concentration on vitamin E encapsulation effect

[0157] The particle size and vitamin E encapsulation rate of the tea oil microcapsules obtained in Examples 1, 6 to 9 were measured. The results are shown in Table 5. As the pectin concentration increases, the particle size of the obtained microcapsules also gradually increases, indicating that the amount of polysaccharide added is not necessarily the more the better. Excessive addition of polysaccharides will cause oil body cell flocculation and reduce the stability of the oil body cell emulsion, resulting in poor encapsulation effect. Therefore, the preferred pectin concentration is 0.3wt% to 2wt%.

[0158] Table 5 Effect of pectin concentration on vitamin E encapsulation effect

[0159] Group Pectin concentration / wt% Particle size / μm <![CDATA[V E Embedding rate / %]]> Emulsion state Example 6 0.3 2.54 86.1 Uniform and stable Example 1 0.6 2.48 94.5 Uniform and stable Example 7 1 2.63 80.5 Uniform and stable Example 8 1.5 2.69 75.3 Uniform and stable Example 9 2 2.73 68.9 Uniform and stable

[0160] Table 5: Pectin concentration refers to the mass fraction concentration of pectin prepared into solution.

[0161] (6) Effect of different vitamin E contents on vitamin E encapsulation effect

[0162] The particle size and vitamin E embedding rate of tea oil microcapsules obtained in Examples 1, 10, 11 and 12 were measured. The results are shown in Table 6. When the vitamin E content is 50%, the size of the microcapsules is uneven, and the microcapsules are aggregated and leaking oil; when the vitamin E content is 40%, the emulsification is sufficient, the microcapsules are evenly distributed, and there is less oil that is not embedded and attached to the surface of the microcapsules; when the vitamin E content is less than 20%, the volume of the oil body cell emulsion accounts for a large proportion, so the capsule wall of the formed microcapsule is thicker, thereby reducing the content of embedded vitamin E, so the preferred vitamin E content is 20% to 40%. The encapsulation rate of vitamin E can reach up to 94.5%,

[0163] Table 6 Effect of vitamin E content on vitamin E embedding effect

[0164] Group Vitamin E content / % Particle size / μm <![CDATA[V E Embedding rate / %]]> Emulsion state Example 10 20％ 2.63 81.3 Uniform and stable Embodiment 11 30％ 2.57 86.8 Uniform and stable Example 1 40％ 2.48 94.5 Uniform and stable Comparative Example 3 50％ 2.69 75.6 Flocculation, oil leakage

[0165] Table 6: Vitamin E content as a percentage of the volume of the Camellia oleifera extract solution.

[0166] (7) Effect of pH adjustment on vitamin E encapsulation

[0167] The particle size and vitamin E embedding rate of tea oil microcapsules obtained in Examples 1, 13-15 and Comparative Examples 4-6 were measured. The results are shown in Table 7. The electrostatic interaction between the surface protein of oil body cells and pectin was adjusted by pH. The electrostatic complex was usually formed at pH 3.0. Pectin is an anionic polysaccharide. Oil body cells contain many cationic groups, such as -NH 3+ , near the isoelectric point of oil body cells (4.0-5.0), the surface charge of oil body cells is close to zero, and oil body cells are easy to aggregate and merge, but after adding pectin, pectin will provide negative charge to destroy the aggregation of oil body cells. However, at higher pH values, there is a strong electrostatic repulsion between oil body cells and pectin, which inhibits the formation of complexes. Therefore, under acidic conditions, the surface protein of oil body cells has a strong binding force with pectin, and the complex formed is conducive to the stability of the tea oil microcapsule system.

[0168] Table 7 Effect of pH on Vitamin E Encapsulation

[0169] Group pH Particle size / μm <![CDATA[V E Embedding rate / %]]> Emulsion state Comparative Example 4 2 3.05 74.3 Uneven Example 1 3 2.48 94.5 Uniform and stable Example 12 4 2.59 93.6 Uniform and stable Example 13 5 2.75 85.4 Uniform and stable Embodiment 14 6 2.83 82.7 Uniform and stable Comparative Example 5 7 3.08 77.6 Slightly delaminated Comparative Example 6 8 3.29 / Obvious stratification, unstable

[0170] Experimental Example 2 Temperature and light stability experiment of tea oil microcapsules

[0171] 1. Experimental methods

[0172] (1) Temperature treatment method

[0173] Take equal amounts of vitamin E microcapsules and free vitamin E oil (used as a blank control) with the same vitamin E content. After storing them in a constant temperature incubator at 4°C, 25°C, and 45°C for 15 days respectively, calculate the vitamin E retention rate according to the following formula.

[0174] (2) Sunlight treatment method

[0175] Take equal amounts of vitamin E microcapsules and free vitamin E oil (used as a blank control) with the same vitamin E content. Store them separately under indoor light and in the dark for 15 days, and calculate the vitamin E retention rate according to the following formula.

[0176] Calculation formula for vitamin E retention rate under different temperature and sunlight conditions:

[0177] Retention rate (%) = (content of vitamin E after temperature or light treatment / total content of vitamin E before temperature or light treatment) × 100%

[0178] 2. Experimental results

[0179] (1) Influence of storage temperature on the storage stability of camellia oil microcapsules

[0180] Measure the particle size, vitamin E encapsulation rate, and vitamin E retention rate of the camellia oil microcapsules obtained in Examples 1 - 3 and Comparative Examples 1 - 3 under different storage conditions. The results are shown in Table 8. As the storage temperature increases, the vitamin E retention rate gradually decreases, indicating that vitamin E is more suitable for storage at low temperatures. Compared with the data of free vitamin E or camellia oil microcapsules prepared by using Tween 80 instead of oil somatic cells, the camellia oil microcapsules with a double-layer core-shell structure maintain good stability under different storage conditions and have a higher vitamin E retention rate.

[0181] Table 8 Influence of different storage temperatures on the storage stability of camellia oil microcapsules

[0182]

[0183] Table 8: The experimental data was analyzed for significance using SPSS software, and the statistical difference (P value) was calculated using an independent samples T-test; among them, P > 0.05 indicates no significant difference; 0.01 < P < 0.05 indicates a significant difference; P < 0.01 indicates a highly significant difference.

[0184] (2) Influence of light treatment conditions on the storage stability of camellia oil microcapsules

[0185] The particle size, vitamin E encapsulation rate of the tea oil microcapsules obtained in Examples 1 to 3 and Comparative Examples 1 to 3, and the retention rate of vitamin E under different light treatment conditions were measured. The results are shown in Table 9. Compared with the data of free vitamin E or tea oil microcapsules prepared by using Tween 80 instead of oil somatic cells, the tea oil microcapsules with a double-layer core-shell structure maintained good stability under different light treatment conditions and had a high vitamin E retention rate.

[0186] Table 9 Effects of different light treatment conditions on the storage stability of oil body microcapsules

[0187]

[0188]

[0189] Table 9: The experimental data was analyzed for significance using SPSS software, and the statistical difference (P value) was calculated using an independent samples T-test; among them, P>0.05 indicates no significant difference; 0.01<P<0.05 indicates a significant difference; P<0.01 indicates a highly significant difference.

[0190] Stability test of the tea oil skin care lotion in Experimental Example 3

[0191] According to GB / T 29665-2013 "National Standard of the People's Republic of China - Skin Care Lotion", the physical and chemical indexes of the skin care lotions obtained in Examples 15 to 17 and Comparative Examples 10 to 12 were tested. The results are shown in Table 10. The tea oil skin care lotions prepared in Examples 15 to 17 had good heat resistance, cold resistance and centrifugal stability, meeting the national standard of skin care lotions; while using the microcapsules prepared by replacing oil somatic cells with Tween 80 to prepare the tea oil skin care lotion, and conducting heat resistance experiments, cold resistance experiments and centrifugal stability experiments on the obtained skin care lotions respectively, the lotions all showed stratification, indicating that the stability of the skin care lotion prepared by using Tween 80 was poor.

[0192] Table 10 Stability results of the tea oil skin care lotions prepared in Examples 15 to 17 and Comparative Examples 10 to 12

[0193] Group pH Heat resistance test Cold resistance test Centrifugal stability test Embodiment 15 4 No stratification No stratification No stratification Example 16 4 No stratification No stratification No stratification Embodiment 17 8 No stratification No stratification No stratification Comparative Example 10 4 Layering Layering Layering Comparative Example 11 4 Layering Layering Layering Comparative Example 12 8 Layering Layering Layering

[0194] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A tea oil microcapsule with a double-layer core-shell structure, characterized in that: The tea oil microcapsules are sequentially arranged from the inside to the outside as a core layer, a first shell layer, and a second shell layer; The core layer is a fat-soluble component; the first shell layer is made of oil body cell emulsion; the second shell layer is mainly made of protein or polysaccharide; The oil body cell emulsion consists of oil body cells and camellia oleifera extract solution; The mass volume ratio of the oil body cells and the camellia oleifera extract solution is 2.5-7.5:50 g / mL; The method for preparing oil body cells comprises the following steps: adding a buffer solution into oil tea seeds, adjusting pH, adding plant complex enzymes for enzymolysis, inactivating enzymes, breaking the wall, filtering, centrifuging, and taking the upper layer to obtain the oil body cells.

2. The tea oil microcapsule according to claim 1, characterized in that: The camellia oleifera extract solution is obtained by extracting camellia oleifera with water.

3. The tea oil microcapsule according to claim 1, characterized in that: The plant complex enzyme is cellulase, hemicellulase, beta-glucanase and pectinase.

4. The tea oil microcapsule according to claim 3, characterized in that: The mass ratio of the cellulase, hemicellulase, beta-glucanase and pectinase is 1-3:0-1:1-2:1-2.

5. The tea oil microcapsule according to claim 1, characterized in that: The mass volume ratio of the camellia seeds to the buffer solution is 1:(4-10) g / mL.

6. The tea oil microcapsule according to claim 1, characterized in that: The pH is 4.5-9.

7. The method for preparing tea oil microcapsules according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. The oil body cells and the camellia oleifera extract solution are thoroughly mixed to form an oil body cell emulsion; S2. adding the fat-soluble component to the oil body cell emulsion obtained in step S1, and mixing thoroughly to obtain a mixed solution; S3. Add the protein or polysaccharide solution into the mixed solution obtained in step S2, mix thoroughly, and adjust the pH to obtain tea oil microcapsules.

8. The preparation method according to claim 7, characterized in that: Calculated by percentage of the volume of the camellia oleifera extract solution, the fat-soluble component accounts for 20% to 40%.

9. Use of the tea oil microcapsules according to any one of claims 1 to 6 in the preparation of medicines, foods or cosmetics.

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