A method for continuously and rapidly synthesizing shell-core structure perfume microcapsules

Abstract

This invention discloses a method for the continuous and rapid synthesis of shell-core structured fragrance microcapsules, belonging to the field of fragrance microcapsule preparation. The method utilizes microfluidic technology to continuously and rapidly synthesize shell-core fragrance microcapsules. First, a precisely controllable shell-core droplet template for encapsulating fragrance is obtained at the front end of a microchannel through fluid shearing. Then, a solidification solution of sodium dodecyl sulfate is introduced at the rear end of the microchannel. Taking advantage of the efficient mass transfer within the microchannel, sodium dodecyl sulfate interacts electrostatically with the chitosan mesophase to form a complex of positive and negative ions. The rate of mass transfer can be controlled by adjusting the concentration of reactants and the flow rate of the fluid, thereby controlling the rate and extent of solidification. Furthermore, the release rate of the fragrance microcapsules can be controlled by adjusting the size, shell thickness, and degree of solidification, enabling continuous and rapid synthesis and controlled release of fragrance microcapsules. The prepared fragrance microcapsules exhibit good monodispersity and an encapsulation efficiency of up to 100%.

Description

Technical Field

[0001] This invention relates to the field of microcapsule preparation technology, and more specifically, to a method for the continuous and rapid synthesis of shell-core structured fragrance microcapsules. Background Technology

[0002] Natural fragrances possess antibacterial, antifungal, antioxidant, and antiviral properties, and are widely used in food, beverages, personal care, and cosmetics. Natural fragrances offer advantages such as health and safety, and low allergenicity, leading consumers to shift their attention from synthetic to natural products in recent years. However, natural fragrances also suffer from drawbacks such as volatility, easy oxidation, and short-lasting scent, significantly impacting their effectiveness in related products.

[0003] Microencapsulation technology can alter the state of natural flavorings, protect sensitive components, control their release rate, isolate different components, mask undesirable flavors and colors, and ultimately reduce the amount of additives required and their toxic side effects. Therefore, designing efficient delivery systems, controlling the slow release of highly volatile flavorings, and improving the stability of flavoring chemical functional groups through controllable microcapsules have become important research areas in the flavoring industry.

[0004] Conventional methods for the microencapsulation of fragrance nanoparticles mainly include coagulation, spray drying, spray freezing, and fluidized bed methods. These preparation methods are primarily batch processes, first forming an emulsion through mechanical stirring, and then drying it through different drying processes such as heating or freezing. Due to the uncontrollability of mechanical stirring, the resulting emulsions are of uneven size and their internal structure is difficult to control, leading to inconsistent microcapsule quality, low encapsulation rates, and engineering problems such as low efficiency and scale-up effects. Summary of the Invention

[0005] Therefore, in order to solve the problems of inconsistent quality, low encapsulation rate, and low production efficiency of microcapsules prepared in the prior art, this invention provides a method for continuous and rapid synthesis of shell-core structured fragrance microcapsules, the specific technical solution of which is as follows:

[0006] A method for continuous and rapid synthesis of shell-core structured fragrance microcapsules, comprising the following steps:

[0007] The essential oil of the fragrance is used as the internal phase solution, which is taken as fluid L1;

[0008] Chitosan was dissolved in water, and then Tween 80 was added to prepare an intermediate phase solution, which was used as fluid L2.

[0009] Take mineral oil, add emulsifier, and prepare external phase solution 1, which serves as fluid L3;

[0010] Sodium dodecyl sulfate was dissolved in water to prepare external phase solution 2, which was used as fluid L4.

[0011] Fluids L1, L2, L3, and L4 are injected into a microfluidic device via an injection pump. Fluids L1, L2, and L3 form an O / W / O droplet template through inter-fluid shearing, which then flows into a receiving tube. Chitosan in fluid L2 undergoes a polymerization reaction with sodium dodecyl sulfate in fluid L4, which then solidifies to obtain a core-shell fragrance microcapsule.

[0012] Furthermore, the essential oil is an oil-soluble essential oil.

[0013] Furthermore, the oil-soluble essential oil is one or more of lavender essential oil, tea tree essential oil, and peppermint essential oil.

[0014] Furthermore, in the fluid L2, the chitosan has a mass percentage concentration of 0.3% to 2%, a molecular weight of 50,000 to 100,000, and a viscosity of 50 mPa·s to 200 mPa·s.

[0015] Furthermore, in the fluid L2, the mass percentage concentration of Tween 80 is 0.2% to 2%.

[0016] Furthermore, the emulsifier is polyglycerol ricinoleate, and the mass percentage concentration of the polyglycerol ricinoleate is 0.5% to 20%.

[0017] Furthermore, the sodium dodecyl sulfate has a mass percentage concentration of 0.5% to 8%.

[0018] Furthermore, the flow rate of fluid L1 is 1 μL / min to 10 μL / min, the flow rate of fluid L2 is 15 μL / min to 50 μL / min, the flow rate of fluid L3 is 40 μL / min to 300 μL / min, and the flow rate of fluid L4 is 30 μL / min to 500 μL / min.

[0019] Furthermore, the length of the receiving pipe is 10cm to 50cm.

[0020] Furthermore, the polymerization reaction takes place over a period of 10 to 120 seconds.

[0021] This invention utilizes microfluidic technology to continuously and rapidly synthesize core-shell fragrance microcapsules. First, a precisely controllable core-shell droplet template encapsulating the fragrance is obtained at the front end of a microchannel through fluid shearing. Then, a curing solution of sodium dodecyl sulfate (fluid L4) is introduced at the rear end of the microchannel. Leveraging the efficient mass transfer within the microchannel, sodium dodecyl sulfate interacts electrostatically with the chitosan mesophase to form a complex of positive and negative ions. The curing reaction can be completed within 1 minute. The rate of mass transfer can be controlled by adjusting the concentration of reactants and the flow rate of the fluid, thereby controlling the rate and extent of curing. Furthermore, the release rate of the fragrance microcapsules can be controlled by adjusting their size, shell thickness, and degree of curing. Therefore, through the above steps and adjustments to the operating parameters, continuous and rapid synthesis and controlled release of fragrance microcapsules can be achieved.

[0022] The present invention enables continuous and rapid synthesis of shell-core structured fragrance microcapsules, avoiding problems such as poor reproducibility and scale-up effects caused by intermittent synthesis.

[0023] The shell-core structured fragrance microcapsules synthesized in this invention exhibit good monodispersity and an encapsulation efficiency of up to 100%.

[0024] The shell-core structured microcapsules synthesized in this invention can regulate the release rate of fragrance by adjusting the concentration of reactants (chitosan concentration or SDS concentration) as well as the size and shell thickness of the capsules.

[0025] The solvents used in the preparation process of this invention are all green and safe, and the preparation conditions are mild and the preparation method is simple, making it suitable for industrial production. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process for the continuous and rapid synthesis of shell-core structured fragrance microcapsules in Embodiment 1 of the present invention;

[0027] Figure 2 This is a microscopic schematic diagram of the fragrance microcapsules synthesized in Example 1 of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] A method for continuous and rapid synthesis of shell-core structured fragrance microcapsules according to one embodiment of the present invention includes the following steps:

[0031] The essential oil of the fragrance is used as the internal phase solution, which is taken as fluid L1;

[0032] Chitosan was dissolved in water, and then Tween 80 was added to prepare an intermediate phase solution, which was used as fluid L2.

[0033] Take mineral oil, add emulsifier, and prepare external phase solution 1, which serves as fluid L3;

[0034] Sodium dodecyl sulfate was dissolved in water to prepare external phase solution 2, which was used as fluid L4.

[0035] Fluids L1, L2, L3, and L4 are injected into a microfluidic device via an injection pump. Fluids L1, L2, and L3 form an O / W / O droplet template through inter-fluid shearing, which then flows into a receiving tube. Chitosan in fluid L2 undergoes a polymerization reaction with sodium dodecyl sulfate in fluid L4, which then solidifies to obtain a core-shell fragrance microcapsule.

[0036] In one embodiment, the fragrance oil is an oil-soluble essential oil.

[0037] In one embodiment, the oil-soluble essential oil is one or more of lavender essential oil, tea tree essential oil, and peppermint essential oil.

[0038] In one embodiment, the chitosan has a mass percentage concentration of 0.3% to 2% in the fluid L2, and the chitosan has a molecular weight of 50,000 to 100,000 and a viscosity of 50 mPa·s to 200 mPa·s.

[0039] In one embodiment, the mass percentage concentration of Tween 80 in the fluid L2 is 0.2% to 2%.

[0040] In one embodiment, the emulsifier is polyglycerol ricinoleate, and the mass percentage concentration of the polyglycerol ricinoleate is 0.5% to 20%.

[0041] In one embodiment, the sodium dodecyl sulfate has a mass percentage concentration of 0.5% to 8%.

[0042] In one embodiment, the flow rate of fluid L1 is 1 μL / min to 10 μL / min, the flow rate of fluid L2 is 15 μL / min to 50 μL / min, the flow rate of fluid L3 is 40 μL / min to 300 μL / min, and the flow rate of fluid L4 is 30 μL / min to 500 μL / min.

[0043] In one embodiment, the length of the receiving pipe is 10cm to 50cm.

[0044] In one embodiment, the polymerization reaction takes 10 to 120 seconds.

[0045] This invention provides a continuous and rapid synthesis of core-shell structured fragrance microcapsules, which are prepared in a green and safe manner, exhibit good dispersibility, and achieve 100% encapsulation efficiency.

[0046] The implementation schemes of the present invention will now be described in detail with reference to specific embodiments.

[0047] Example 1:

[0048] A method for continuous and rapid synthesis of shell-core structured fragrance microcapsules, comprising the following steps:

[0049] Lavender essential oil was used as the internal phase solution (fluid L1);

[0050] Prepare a chitosan solution with a mass percentage concentration of 1%, add Tween 80 with a mass percentage concentration of 1%, and use a syringe to draw it up as an intermediate phase solution (fluid L2).

[0051] Add 5% by weight of polyglycerol ricinoleate to mineral oil to prepare external phase solution 1 (fluid L3);

[0052] Prepare a 3% (w / w) sodium dodecyl sulfate aqueous solution (curing solution) to form external phase solution 2 (fluid L4);

[0053] The flow rates of fluids L1, L2, L3, and L4 were 5 μL / min, 30 μL / min, 100 μL / min, and 100 μL / min, respectively, and solidified into spherical core-shell fragrance microcapsules within a receiving tube, wherein the length of the receiving tube was 20 cm.

[0054] Example 1 demonstrates a continuous and rapid preparation of fragrance microcapsules with good dispersibility, uniform overall size, guaranteed quality, and 100% encapsulation efficiency. The prepared fragrance microcapsules have a total diameter of 500 micrometers, a core diameter of 236 micrometers, and a shell thickness of 132 micrometers. After 24 hours of microcapsule release at room temperature, 60% of the lavender essential oil remains.

[0055] Example 2:

[0056] A method for continuous and rapid synthesis of shell-core structured fragrance microcapsules, comprising the following steps:

[0057] Lavender essential oil was used as the internal phase solution (fluid L1);

[0058] Prepare a chitosan solution with a mass percentage concentration of 1%, then add Tween 80 with a mass percentage of 1%, and use a syringe to draw it up as an intermediate phase solution (fluid L2);

[0059] Add 5% polyglycerol ricinoleate to mineral oil to prepare external phase solution 1 (fluid L3); prepare 3% sodium dodecyl sulfate aqueous solution (curing solution) to prepare external phase solution 2 (fluid L4).

[0060] The flow rates of fluids L1, L2, L3, and L4 are all 100 μL / min, and are solidified into spherical core-shell fragrance microcapsules within a receiving tube, wherein the length of the receiving tube is 20 cm.

[0061] Example 2 demonstrates a continuous and rapid preparation of fragrance microcapsules with good dispersibility, uniform overall size, guaranteed quality, and 100% encapsulation efficiency. The resulting fragrance microcapsules have a total diameter of 500 micrometers, a core diameter of 318 micrometers, and a shell thickness of 91 micrometers. After 24 hours of microcapsule release at room temperature, 45% of the lavender essential oil remains.

[0062] Example 3:

[0063] A method for continuous and rapid synthesis of shell-core structured fragrance microcapsules, comprising the following steps:

[0064] Lavender essential oil was used as the internal phase solution (fluid L1);

[0065] Prepare a chitosan solution with a mass percentage concentration of 1%, then add Tween 80 with a mass percentage concentration of 1%, and use a syringe to draw it up as an intermediate phase solution (fluid L2).

[0066] Add 5% polyglycerol ricinoleate by mass percentage to mineral oil to prepare external phase solution 1 (fluid L3);

[0067] Prepare a 1% (w / w) sodium dodecyl sulfate aqueous solution (curing solution) to form external phase solution 2 (fluid L4);

[0068] The flow rates of fluids L1, L2, L3, and L4 were all set at 5 μL / min, 30 μL / min, 100 μL / min, and 100 μL / min, respectively. These fluids were then solidified into spherical core-shell fragrance microcapsules within a receiving tube, wherein the length of the receiving tube was 20 cm.

[0069] Example 3 demonstrates a continuous and rapid preparation of fragrance microcapsules with good dispersibility, uniform overall size, guaranteed quality, and 100% encapsulation efficiency. The resulting fragrance microcapsules have a total diameter of 500 micrometers, a core diameter of 236 micrometers, and a shell thickness of 132 micrometers. After 24 hours of microcapsule release at room temperature, 53% of the lavender essential oil remains.

[0070] Example 4:

[0071] A method for continuous and rapid synthesis of shell-core structured fragrance microcapsules, comprising the following steps:

[0072] Lavender essential oil was used as the internal phase solution (fluid L1);

[0073] Prepare a chitosan solution with a mass percentage concentration of 1%, then add Tween 80 with a mass percentage concentration of 1%, and use a syringe to draw it up as an intermediate phase solution (fluid L2).

[0074] Add 5% by weight of polyglycerol ricinoleate to mineral oil to prepare external phase solution 1 (fluid L3);

[0075] Prepare a 5% (w / w) sodium dodecyl sulfate aqueous solution (curing solution) to form external phase 2 (fluid L4);

[0076] The flow rates of fluids L1, L2, L3, and L4 were all 5 μL / min, 30 μL / min, 100 μL / min, and 100 μL / min, respectively. These fluids were then solidified into spherical core-shell fragrance microcapsules within a receiving tube, wherein the length of the receiving tube was 20 cm.

[0077] Example 4 demonstrates a continuous and rapid preparation of fragrance microcapsules with good monodispersity, uniform overall size, guaranteed quality, and 100% encapsulation efficiency. The resulting fragrance microcapsules have a total diameter of 500 micrometers, a core diameter of 236 micrometers, and a shell thickness of 132 micrometers. After 24 hours of microcapsule release at room temperature, 75% of the lavender essential oil remains.

[0078] As can be seen from Examples 1 to 4 above, the release rate of fragrance can be controlled by adjusting the concentration of reactants and the size and shell thickness of the fragrance capsule.

[0079] Example 5:

[0080] The difference from Example 4 is that in Comparative Example 1, the flow rate of fluid L1 is 10 μL / min, the flow rate of fluid L2 is 35 μL / min, the flow rate of fluid L3 is 80 μL / min, and the flow rate of fluid L4 is 120 μL / min. Otherwise, they are the same as in Example 4.

[0081] The fragrance microcapsules prepared in Example 5 exhibited good monodispersity, uniform overall size, and guaranteed quality, with a 100% encapsulation rate. The resulting fragrance microcapsules had a total diameter of 600 micrometers, a core diameter of 400 micrometers, and a shell thickness of 100 micrometers. After 24 hours of microcapsule release at room temperature, 53% of the lavender essential oil remained.

[0082] Example 6:

[0083] The difference from Example 4 is that in Comparative Example 2, the flow rate of fluid L1 is 10 μL / min, the flow rate of fluid L2 is 15 μL / min, the flow rate of fluid L3 is 30 μL / min, and the flow rate of fluid L4 is 150 μL / min. Otherwise, they are the same as in Example 4.

[0084] The fragrance microcapsules prepared in Example 6 exhibited good monodispersity, uniform overall size, and guaranteed quality, with a 100% encapsulation rate. The resulting fragrance microcapsules had a total diameter of 600 micrometers, a core diameter of 240 micrometers, and a shell thickness of 180 micrometers. After 24 hours of microcapsule release at room temperature, 81% of the lavender essential oil remained.

[0085] Example 7:

[0086] The difference from Example 4 is that in Comparative Example 3, the flow rate of fluid L1 is 5 μL / min, the flow rate of fluid L2 is 20 μL / min, the flow rate of fluid L3 is 45 μL / min, and the flow rate of fluid L4 is 200 μL / min. Otherwise, they are the same as in Example 4.

[0087] The fragrance microcapsules prepared in Example 7 exhibited good monodispersity, uniform overall size, and guaranteed quality, with a 100% encapsulation rate. The resulting fragrance microcapsules had a total diameter of 420 micrometers, a core diameter of 220 micrometers, and a shell thickness of 100 micrometers. After 24 hours of microcapsule release at room temperature, 56% of the lavender essential oil remained.

[0088] As can be seen from Examples 1 to 7, adjusting the flow rate does not affect the quality of the capsules, and the overall production quality remains stable. What is affected is the size and shell thickness of the capsules, which can be used to control the release of the capsules. Therefore, the desired release amount of flavor microcapsules can be obtained by adjusting the flow rate.

[0089] Comparative Example 1:

[0090] A method for synthesizing flavor microcapsules, the method comprising the following steps:

[0091] Lavender essential oil was mixed with a 1% (w / w) chitosan solution, a 1% (w / w) Tween 80 solution, mineral oil, a 5% (w / w) polyglycerol ricinoleate solution, and a 5% (w / w) sodium dodecyl sulfate aqueous solution. The mixture was then homogenized at 12000 r / min for 10 min to obtain the final product. The crude emulsion was then further processed three times using an ultra-high pressure microfluidic homogenizer at a homogenization pressure of 25 MPa. After stirring, an emulsion was prepared. Finally, the emulsion was spray-dried to obtain fragrance microcapsules.

[0092] In Comparative Example 1, the production of fragrance microcapsules was inefficient, the stirring process was not controllable, the emulsions were uneven in size, and the internal structure of the emulsions was difficult to control. As a result, the quality of the prepared microcapsules was inconsistent, the encapsulation rate was low, and there were also engineering problems such as efficiency of less than 50% and scale-up effect.

[0093] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for continuous and rapid synthesis of shell-core structured fragrance microcapsules, characterized in that, Integrated continuous synthesis is performed using a microfluidic device, which includes a front-end microchannel and a rear-end receiving tube. The synthesis method includes the following steps: The essential oil of the fragrance is used as the internal phase solution, which is taken as fluid L1; Chitosan was dissolved in water, and then Tween 80 was added to prepare an intermediate phase solution, which was used as fluid L2. Take mineral oil, add emulsifier, and prepare external phase solution 1, which serves as fluid L3; Sodium dodecyl sulfate was dissolved in water to prepare external phase solution 2, which was used as fluid L4. Fluids L1, L2, L3, and L4 are injected into a microfluidic device via an injection pump. Fluids L1, L2, and L3 are used to prepare an O / W / O droplet template through inter-fluid shearing. The template then flows into a receiving tube. Chitosan in fluid L2 undergoes a polymerization reaction with sodium dodecyl sulfate in fluid L4 for 10-120 seconds, which solidifies to obtain a core-shell fragrance microcapsule.

2. The method for continuous and rapid synthesis of shell-core structured fragrance microcapsules according to claim 1, characterized in that, The essential oils mentioned are oil-soluble.

3. The method for continuous and rapid synthesis of shell-core structured fragrance microcapsules according to claim 2, characterized in that, The oil-soluble essential oil is one or more of lavender essential oil, tea tree essential oil, and peppermint essential oil.

4. The method for continuous and rapid synthesis of shell-core structured fragrance microcapsules according to claim 1, characterized in that, In the fluid L2, the chitosan has a mass percentage concentration of 0.3% to 2%, a molecular weight of 50,000 to 100,000, and a viscosity of 50 mPa·s to 200 mPa·s.

5. The method for continuous and rapid synthesis of shell-core structured fragrance microcapsules according to claim 1, characterized in that, In the fluid L2, the mass percentage concentration of Tween 80 is 0.2% to 2%.

6. The method for continuous and rapid synthesis of shell-core structured fragrance microcapsules according to claim 1, characterized in that, The emulsifier is polyglycerol ricinoleate, and the mass percentage concentration of the polyglycerol ricinoleate is 0.5% to 20%.

7. The method for continuous and rapid synthesis of shell-core structured fragrance microcapsules according to claim 1, characterized in that, The sodium dodecyl sulfate has a mass percentage concentration of 0.5% to 8%.

8. The method for continuous and rapid synthesis of shell-core structured fragrance microcapsules according to claim 1, characterized in that, The flow rate of fluid L1 is 1 μL / min ~ 10 μL / min, the flow rate of fluid L2 is 15 μL / min ~ 50 μL / min, the flow rate of fluid L3 is 40 μL / min ~ 300 μL / min, and the flow rate of fluid L4 is 30 μL / min ~ 500 μL / min.

9. The method for continuous and rapid synthesis of shell-core structured fragrance microcapsules according to claim 1, characterized in that, The length of the receiving pipe is 10cm to 50cm.

Images