Plant essential oil microcapsule coating preparation process based on hydroxypropyl-beta-cyclodextrin

Abstract

The invention discloses a hydroxypropyl-beta-cyclodextrin-based plant essential oil microcapsule coating preparation process. The process comprises the following process steps: step 1, ultrasonic pretreatment, step 2, microwave-assisted reaction, step 3, preparation of a core material solution, step 4, preparation of a wall material solution, step 5, primary embedding, and step 6, secondary embedding. The plant essential oil molecules are better dispersed and interact with the wall material through ultrasonic pretreatment, and the binding sites of the plant essential oil and the wall material are increased. The microwave-assisted reaction further promotes the interaction between plant essential oil molecules and components such as sodium tripolyphosphate, so that the combination between the molecules is tighter, the combination sites are further increased, the embedding rate is improved, chitosan oligosaccharide and Arabic gum in the composite wall material can form a more stable compound with the plant essential oil molecules, and the embedding efficiency is improved. The embedding effect is further improved.

Description

Technical Field

[0001] This invention relates to the field of thin-walled part processing technology, specifically to a process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin. Background Technology

[0002] Plant essential oils are volatile aromatic compounds extracted from the flowers, leaves, stems, roots, fruits, seeds, resins, and other parts of plants, and have a variety of properties and applications. Plant essential oils possess a variety of biological activities, such as antibacterial, antioxidant, and insecticidal properties, and have broad application prospects in the fields of food, medicine, and cosmetics. However, the volatility and instability of plant essential oils limit their application. Microencapsulation technology can encapsulate plant essential oils in wall materials, improving their stability and controllable release. Traditional methods for preparing plant essential oil microcapsules have problems such as low encapsulation rate, poor encapsulation effect on complex essential oil systems, insufficient long-term storage stability, and poor stability in different media. Hydroxypropyl-β-cyclodextrin, as a commonly used wall material component, has good encapsulation performance, but its effect is limited when used alone. Therefore, we propose a process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin. Summary of the Invention

[0003] The purpose of this invention is to provide a process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin, which solves the problem mentioned in the background art that hydroxypropyl-β-cyclodextrin, as a commonly used wall material component, has good encapsulation performance, but its effect is limited when used alone.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin, comprising the following process steps: Step 1: Ultrasonic pretreatment: Mix plant essential oil and anhydrous ethanol at a mass ratio of 1:(2-5) to obtain a plant essential oil ethanol solution. Prepare a sodium tripolyphosphate aqueous solution with a mass fraction of 0.5%-2%. Slowly add the plant essential oil ethanol solution to the sodium tripolyphosphate aqueous solution. The volume ratio of plant essential oil to sodium tripolyphosphate aqueous solution is 1:(5-10) to obtain a pretreatment solution. Ultrasonically treat the pretreatment solution at 40-60℃ and 100-300W for 15-30 minutes. Step 2: Microwave-assisted reaction: Transfer the pretreated solution after ultrasonic treatment to a microwave reactor and treat it at 50-80℃ and microwave power of 200-500W for 5-15 minutes. Step 3: Preparation of core material solution: Add lecithin to the solution after microwave-assisted reaction, heat to 50-70℃ to completely dissolve it, and the mass ratio of plant essential oil to lecithin is (1-5):2; Step 4: Preparation of wall material solution: Add the wall material containing hydroxypropyl-β-cyclodextrin, sodium octenyl succinate starch, emulsified modified starch, chitosan oligosaccharide and gum arabic to water, stir at 50-70℃ for 1-2 hours, the mass ratio of wall material to water is 1:(4-10), add emulsifier and mix and stir for 20-30 minutes. Step 5: Initial encapsulation: Add the core material solution to the wall material solution, stir at 40-60℃ for 20-60 min, homogenize and emulsify the mixture using a homogenizer, and obtain monolayer microcapsules after drying; Step 6: Secondary encapsulation: Add the monolayer microcapsules to the sodium alginate solution and stir until homogeneous. Then add chitosan and calcium chloride and stir until homogeneous. Sonicate for 5-10 minutes, filter and dry to obtain the bilayer microcapsules.

[0005] In a preferred embodiment of the present invention, the mass fractions of each component in the wall material are: 60-80 parts of hydroxypropyl-β-cyclodextrin, 10-25 parts of sodium octenyl succinate starch, 5-12 parts of emulsified modified starch, 3-8 parts of chitosan oligosaccharide, and 2-6 parts of gum arabic.

[0006] In a preferred embodiment of the present invention, the emulsifier is 5-10 parts by mass and may be one or a mixture of polyether-modified organosilicon, polyether-modified organofluorine, alkyl polyether, Tween-40, Tween-60, Tween-80, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate.

[0007] In a preferred embodiment of the present invention, the homogenization emulsification includes primary homogenization and secondary homogenization. Primary homogenization is carried out at a pressure of 100-500 bar and a rotation speed of 5000-20000 rpm for 5-20 minutes. Secondary homogenization involves adding liquid paraffin to the emulsion obtained from primary homogenization and homogenizing again for 5-20 minutes. The amount of liquid paraffin added is 0.5-2 wt% of the total mass of the emulsion.

[0008] In a preferred embodiment of the present invention, the drying method may be selected from vacuum drying, freeze drying, or spray drying.

[0009] In a preferred embodiment of the present invention, the sodium alginate solution comprises 3-8 wt% sodium alginate, 2-4 wt% polyethylene glycol and 1 wt% dibutyltin dilaurate.

[0010] In a preferred embodiment of the present invention, the concentration of chitosan in the mixture is 2-3 wt%, and the concentration of calcium chloride in the mixture is 0.5-2 wt%.

[0011] In a preferred embodiment of the present invention, the plant essential oil is a mixture of multiple components.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention utilizes ultrasonic pretreatment to better disperse plant essential oil molecules and facilitate their interaction with the wall material, increasing the binding sites between the plant essential oils and the wall material. Microwave-assisted reaction further promotes the interaction between plant essential oil molecules and components such as sodium tripolyphosphate, resulting in tighter intermolecular bonding and further increasing the binding sites, which is beneficial for improving the encapsulation rate. Furthermore, the chitosan oligosaccharides and gum arabic in the composite wall material can form more stable complexes with plant essential oil molecules, further enhancing the encapsulation effect. For plant essential oils with multiple components, ultrasonic pretreatment and microwave-assisted reaction can better disperse different components and form a uniform encapsulation system with the wall material. The synergistic effect of the composite wall material can also better adapt to the properties of different components and improve the encapsulation effect of complex essential oil systems. The pre-embedding system formed by ultrasonic pretreatment and microwave-assisted reaction exhibits stronger structural stability, reducing the volatilization and leakage of plant essential oils during storage. Chitosan oligosaccharides and gum arabic in the composite wall material possess excellent film-forming properties, enabling the formation of a denser wall material structure, which is beneficial for improving essential oil retention under high temperature, high humidity, and light conditions. The optimization of composite wall materials enables microcapsules to have better adaptability in different media. Chitosan oligosaccharide and gum arabic can interact with the components in the medium, regulate the surface properties of microcapsules, reduce the expansion and rupture of microcapsules in different media, and improve the stability of microcapsules in different media. Attached Figure Description

[0013] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart illustrating the process of preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin according to the present invention. Detailed Implementation

[0014] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments. Example

[0015] Ultrasonic pretreatment: Plant essential oil and anhydrous ethanol were mixed evenly at a mass ratio of 1:2 to obtain a plant essential oil ethanol solution. A sodium tripolyphosphate aqueous solution with a mass fraction of 0.5% was prepared. The plant essential oil ethanol solution was slowly added dropwise to the sodium tripolyphosphate aqueous solution. The volume ratio of plant essential oil to sodium tripolyphosphate aqueous solution was 1:5 to obtain a pretreatment solution. The pretreatment solution was placed in an ultrasonic cleaner and ultrasonically treated for 15 minutes at 40℃ and 100W power.

[0016] Microwave-assisted reaction: The pretreated solution after ultrasonic treatment was transferred to a microwave reactor and treated for 5 min at 50°C and 200W microwave power.

[0017] Core material solution preparation: Add lecithin to the solution after microwave-assisted reaction, heat to 50℃ to completely dissolve it, and the mass ratio of plant essential oil to lecithin is 1:2.

[0018] Preparation of wall material solution: Add the wall material containing 60 parts of hydroxypropyl-β-cyclodextrin, 10 parts of sodium octenyl succinate starch, 5 parts of emulsified modified starch, 3 parts of chitosan oligosaccharide and 2 parts of gum arabic to water, stir at 50°C for 1 hour, the mass ratio of wall material to water is 1:4, add 5 parts of emulsifier (polyether modified organosilicon is selected) and mix and stir for 20-30 minutes.

[0019] Primary encapsulation: The core material solution was added to the wall material solution and stirred at 40°C for 20 minutes. The mixture of the core material solution and the wall material solution was then homogenized and emulsified using a homogenizer. The first homogenization was performed at 100 bar pressure and 5000 rpm for 5 minutes. The second homogenization involved adding liquid paraffin to the emulsion obtained from the first homogenization, with the amount of liquid paraffin added being 0.5 wt% of the total emulsion mass. The mixture was then homogenized again for 5 minutes. The emulsion system was dried using vacuum drying to obtain monolayer microcapsules.

[0020] Secondary encapsulation: The monolayer microcapsules obtained from the initial encapsulation were added to a sodium alginate solution consisting of 3 wt% sodium alginate, 2 wt% polyethylene glycol, and 1 wt% dibutyltin dilaurate. The mixture was stirred at 50°C until homogeneous to obtain a homogeneous solution. Chitosan and calcium chloride were then added to the homogeneous solution and stirred until homogeneous. The mixture was ultrasonically treated for 5 min. The concentration of chitosan in the mixture was 2 wt%, and the concentration of calcium chloride in the mixture was 0.5 wt%. After filtration and drying, bilayer microcapsules were obtained. Example

[0021] Ultrasonic pretreatment: Plant essential oil and anhydrous ethanol were mixed evenly at a mass ratio of 1:3 to obtain a plant essential oil ethanol solution. A 1% sodium tripolyphosphate aqueous solution was prepared. The plant essential oil ethanol solution was slowly added dropwise to the sodium tripolyphosphate aqueous solution at a volume ratio of 1:7 to obtain a pretreatment solution. The pretreatment solution was placed in an ultrasonic cleaner and ultrasonically treated for 20 minutes at 50℃ and 200W.

[0022] Microwave-assisted reaction: The pretreated solution after ultrasonic treatment was transferred to a microwave reactor and treated at 60°C and 300W for 10 minutes.

[0023] Core material solution preparation: Add lecithin to the solution after microwave-assisted reaction, heat to 60℃ to completely dissolve it, and the mass ratio of plant essential oil to lecithin is 3:2.

[0024] Preparation of the wall material solution: Add the wall material containing 70 parts of hydroxypropyl-β-cyclodextrin, 18 parts of sodium octenyl succinate starch, 8 parts of emulsified modified starch, 5 parts of chitosan oligosaccharide and 4 parts of gum arabic to water, stir at 60°C for 1.5 h, the mass ratio of wall material to water is 1:7, add 8 parts of emulsifier (Tween-60 and sodium dodecyl sulfate are mixed at a mass ratio of 1:1), mix and stir for 25 min.

[0025] Initial encapsulation: The core material solution was added to the wall material solution and stirred at 50°C for 40 min. The mixture of the core material solution and the wall material solution was homogenized and emulsified using a homogenizer. The first homogenization was performed at 300 bar pressure and 10,000 rpm for 10 min. The second homogenization involved adding liquid paraffin to the emulsion obtained from the first homogenization, with the amount of liquid paraffin added being 1 wt% of the total emulsion mass. The mixture was homogenized again for 10 min. The emulsion system was then freeze-dried to obtain monolayer microcapsules.

[0026] Secondary encapsulation: The monolayer microcapsules obtained from the initial encapsulation were added to a sodium alginate solution consisting of 5 wt% sodium alginate, 3 wt% polyethylene glycol, and 1 wt% dibutyltin dilaurate. The mixture was stirred at 55°C until homogeneous to obtain a homogeneous solution. Chitosan and calcium chloride were then added to the homogeneous solution and stirred until homogeneous. The mixture was ultrasonically treated for 8 min. The concentration of chitosan in the mixture was 2.5 wt%, and the concentration of calcium chloride in the mixture was 1 wt%. After filtration and drying, bilayer microcapsules were obtained. Example

[0027] Ultrasonic pretreatment: Plant essential oil and anhydrous ethanol are mixed evenly at a mass ratio of 1:5 to obtain a plant essential oil ethanol solution. A 2% sodium tripolyphosphate aqueous solution is prepared. The plant essential oil ethanol solution is slowly added dropwise to the sodium tripolyphosphate aqueous solution at a volume ratio of 1:10 to obtain a pretreatment solution. The pretreatment solution is placed in an ultrasonic cleaner and ultrasonically treated for 30 minutes at 60℃ and 300W. Microwave-assisted reaction: The pretreated solution after ultrasonic treatment was transferred to a microwave reactor and treated at 80°C and 500W for 15 minutes.

[0028] Preparation of core material solution: Add lecithin to the solution after microwave-assisted reaction, heat to 70℃ to dissolve it completely, and the mass ratio of plant essential oil to lecithin is 5:2.

[0029] Preparation of wall material solution: Add the wall material containing 80 parts of hydroxypropyl-β-cyclodextrin, 25 parts of sodium octenyl succinate starch, 12 parts of emulsified modified starch, 8 parts of chitosan oligosaccharide and 6 parts of gum arabic to water, stir at 70°C for 2 hours, the mass ratio of wall material to water is 1:10, add 10 parts of emulsifier (using polyether modified organic fluorine, alkyl polyether and Tween-80 mixed in a mass ratio of 1:1:1), mix and stir for 30 minutes.

[0030] Primary encapsulation: The core material solution was added to the wall material solution and stirred at 60°C for 60 min. The mixture of core material and wall material solutions was then homogenized and emulsified using a homogenizer. The first homogenization was performed at 500 bar pressure and 20,000 rpm for 20 min. The second homogenization involved adding liquid paraffin (2 wt% of the total emulsion mass) to the emulsion obtained from the first homogenization and homogenizing again for 20 min. The emulsion system was then dried using spray drying to obtain monolayer microcapsules.

[0031] Secondary encapsulation: The monolayer microcapsules obtained from the initial encapsulation were added to a sodium alginate solution consisting of 8 wt% sodium alginate, 4 wt% polyethylene glycol, and 1 wt% dibutyltin dilaurate. The mixture was stirred at 60°C until homogeneous to obtain a homogeneous solution. Chitosan and calcium chloride were then added to the homogeneous solution and stirred until homogeneous. The mixture was ultrasonically treated for 10 min. The concentration of chitosan in the mixture was 3 wt%, and the concentration of calcium chloride in the mixture was 2 wt%. After filtration and drying, bilayer microcapsules were obtained.

[0032] Preparation of core material solution: Mix plant essential oil and lecithin at a mass ratio of 3:2, and heat to 60℃ to completely dissolve them.

[0033] Preparation of wall material solution: Add 80 parts of hydroxypropyl-β-cyclodextrin to water and stir at 60℃ for 1.5h. The mass ratio of wall material to water is 1:7. Add 8 parts of emulsifier (Tween-60) and mix and stir for 25min.

[0034] Encapsulation: The core material solution was added to the wall material solution and stirred at 50°C for 40 min. The mixture was then homogenized and emulsified using a homogenizer at 300 bar pressure and 10,000 rpm for 10 min. The emulsion system was then freeze-dried to obtain microcapsules.

[0035] The performance data obtained from experiments of Examples 1-3 and the comparative examples are shown in the table below: The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0036] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin, characterized in that: The process includes the following steps: Step 1: Ultrasonic pretreatment: Mix plant essential oil and anhydrous ethanol at a mass ratio of 1:(2-5) to obtain a plant essential oil ethanol solution. Prepare a sodium tripolyphosphate aqueous solution with a mass fraction of 0.5%-2%. Slowly add the plant essential oil ethanol solution to the sodium tripolyphosphate aqueous solution. The volume ratio of plant essential oil to sodium tripolyphosphate aqueous solution is 1:(5-10) to obtain a pretreatment solution. Ultrasonically treat the pretreatment solution at 40-60℃ and 100-300W for 15-30 minutes. Step 2: Microwave-assisted reaction: Transfer the pretreated solution after ultrasonic treatment to a microwave reactor and treat it at 50-80℃ and microwave power of 200-500W for 5-15 minutes. Step 3: Preparation of core material solution: Add lecithin to the solution after microwave-assisted reaction, heat to 50-70℃ to completely dissolve it, and the mass ratio of plant essential oil to lecithin is (1-5):2; Step 4: Preparation of wall material solution: Add the wall material containing hydroxypropyl-β-cyclodextrin, sodium octenyl succinate starch, emulsified modified starch, chitosan oligosaccharide and gum arabic to water, stir at 50-70℃ for 1-2 hours, the mass ratio of wall material to water is 1:(4-10), add emulsifier and mix and stir for 20-30 minutes. Step 5: Initial encapsulation: Add the core material solution to the wall material solution, stir at 40-60℃ for 20-60 min, homogenize and emulsify the mixture using a homogenizer, and obtain monolayer microcapsules after drying; Step 6: Secondary encapsulation: Add the monolayer microcapsules to the sodium alginate solution and stir until homogeneous. Then add chitosan and calcium chloride and stir until homogeneous. Sonicate for 5-10 minutes, filter and dry to obtain the bilayer microcapsules.

2. The process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin according to claim 1, characterized in that: The wall material comprises the following components in parts by weight: 60-80 parts of hydroxypropyl-β-cyclodextrin, 10-25 parts of sodium octenyl succinate starch, 5-12 parts of emulsified modified starch, 3-8 parts of chitosan oligosaccharide, and 2-6 parts of gum arabic.

3. The process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin according to claim 1, characterized in that: The emulsifier is 5-10 parts by mass and can be one or a mixture of polyether-modified silicone, polyether-modified fluorine, alkyl polyether, Tween-40, Tween-60, Tween-80, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate.

4. The process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin according to claim 1, characterized in that: The homogenization emulsification includes primary homogenization and secondary homogenization. Primary homogenization is carried out at a pressure of 100-500 bar and a rotation speed of 5000-20000 rpm for 5-20 minutes. Secondary homogenization involves adding liquid paraffin to the emulsion obtained from primary homogenization and homogenizing again for 5-20 minutes. The amount of liquid paraffin added is 0.5-2 wt% of the total mass of the emulsion.

5. The process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin according to claim 1, characterized in that: The drying method may be one of vacuum drying, freeze drying, or spray drying.

6. The process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin according to claim 1, characterized in that: The sodium alginate solution comprises 3-8 wt% sodium alginate, 2-4 wt% polyethylene glycol, and 1 wt% dibutyltin dilaurate.

7. The process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin according to claim 1, characterized in that: The concentration of chitosan in the mixture is 2-3 wt%, and the concentration of calcium chloride in the mixture is 0.5-2 wt%.

8. The process for preparing plant essential oil microcapsule coating based on hydroxypropyl-β-cyclodextrin according to claim 1, characterized in that: The plant essential oil is a mixture of multiple components.

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