Foeniculum vulgare essential oil microcapsule and preparation method thereof

Abstract

The invention relates to the technical field of fennel essential oil microcapsule preparation, and particularly discloses a fennel essential oil microcapsule and a preparation method thereof.The fennel essential oil microcapsule comprises a capsule core and a capsule wall wrapping the capsule core, the capsule core contains fennel essential oil, and the capsule wall contains protein and first polysaccharide; the protein and the first polysaccharide are cross-linked through a Maillard reaction to form a composite wall material, the protein is selected from at least one of whey protein isolate, soybean protein isolate, pea protein and zein, and the first polysaccharide is selected from at least one of Arabic gum, pectin, chitosan and sodium carboxymethyl cellulose. And the capsule wall also comprises a composite additive. According to the fennel essential oil microcapsule and the preparation method thereof, more than 90% of fennel essential oil is efficiently encapsulated, and the oxidation stability and shelf life of the fennel essential oil microcapsule are fundamentally prolonged through an internal and external synergistic active anti-oxidation network and a multi-layer compact physical barrier.

Description

Technical Field

[0001] This invention relates to the field of fennel essential oil microcapsule preparation technology, specifically to a fennel essential oil microcapsule and its preparation method. Background Technology

[0002] Fennel essential oil is widely used due to its unique flavor and physiological activity, but its volatility and susceptibility to oxidation severely limit its processing and storage stability. Microencapsulation technology is an effective protective measure, with wall materials based on the Maillard reaction products of proteins and polysaccharides attracting attention due to their superior interfacial properties; however, their protection of the core material under long-term, harsh environments remains insufficient. To further enhance stability, existing technologies attempt to electrostatically deposit multilayer polysaccharides or introduce functional nanocarriers such as liposomes onto the outside of the primary emulsion. However, the former suffers from cumbersome processes and easy dissociation of the interfacial layer; the latter faces two major bottlenecks: poor physicochemical stability of the nanocarrier itself and weak interfacial bonding with the main wall material, making it difficult to achieve a lasting synergistic stabilizing effect. Therefore, there is an urgent need to develop a novel microencapsulation system that can simultaneously construct a stable primary interface and introduce a highly stable composite additive that can strongly bind to it, in order to fundamentally improve the encapsulation and long-term protective performance of fennel essential oil.

[0003] Chinese patent CN118874355A discloses an essential oil microcapsule and its preparation and application, comprising: using a compound essential oil as the core material and chitosan quaternary ammonium salt and gelatin as the wall material, and preparing the compound essential oil microcapsule by a complex coagulation method, wherein the compound essential oil is selected from any two of thyme, oregano, eucalyptus, clove, lavender, lemongrass, or citronella essential oils. Compared with the prior art, the present invention has the advantages of high efficiency, broad spectrum, and safe antibacterial properties. However, this preparation method cannot achieve efficient encapsulation of essential oils, and its oxidative stability and shelf life cannot be fundamentally extended. Furthermore, it cannot impart excellent physical stability, intelligent sustained-release properties, and excellent thermal processing tolerance to the product, resulting in the inability to maintain the flavor of the final product for a longer period of time. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides: a fennel essential oil microcapsule, comprising a core and a capsule wall encapsulating the core, wherein the core contains fennel essential oil, and the capsule wall contains a protein and a first polysaccharide, wherein the protein and the first polysaccharide are cross-linked through a Maillard reaction to form a composite wall material.

[0005] Preferably, the protein is selected from at least one of whey protein isolate, soy protein isolate, pea protein, and zein.

[0006] Preferably, the first polysaccharide is selected from at least one of gum arabic, pectin, chitosan, and sodium carboxymethyl cellulose.

[0007] Preferably, the capsule wall further comprises a composite additive, the composite additive being prepared as follows:

[0008] S1. Preparation of lipid films:

[0009] Accurately weigh 100mg of soybean lecithin, 20mg of cholesterol, and 30mg of tea polyphenols, and dissolve them together in a 10mL mixture of anhydrous ethanol and chloroform. Place the mixture in a round-bottom flask, connect the flask to a rotary evaporator, and evaporate under reduced pressure at a water bath of 40℃ for 60-90 minutes until a uniform and dry lipid-polyphenol composite film is formed on the flask wall. Continue drying under reduced pressure for 2 hours to ensure complete removal of organic solvent residues.

[0010] S2, Liposome hydration and primary dispersion:

[0011] Add 10 mL of preheated phosphate buffer to the above-mentioned dried film, and hydrate it by rotating at 200 rpm for 60 minutes at the same temperature to completely detach and disperse the film, forming a milky white suspension containing large-diameter multi-compartment liposomes.

[0012] S3. Liposome homogenization and refinement:

[0013] The above crude liposome suspension was first treated with a probe-type ultrasonic cell disruptor under ice-water bath conditions to obtain liposomes with smaller particle size. In order to further obtain liposomes with uniform particle size, the ultrasonicated liquid was passed through a liposome extruder and then through polycarbonate membranes with pore sizes of 400 nm and 200 nm in sequence, extruded 10-15 times each, to obtain a small single-chamber liposome dispersion with a particle size distribution of 150-250 nm and encapsulated tea polyphenols.

[0014] S4, cationic polymer coating:

[0015] To prepare a 1 mg / mL chitosan solution: Dissolve CS in a 1% acetic acid solution and stir magnetically overnight. Adjust the pH to 5.5 with NaOH. Under magnetic stirring, slowly add the dispersion of small single-chamber liposomes encapsulated with tea polyphenols to an equal volume of CS solution. Continue stirring at room temperature for 60 minutes. During the reaction, the negatively charged liposomes and the positively charged chitosan self-assemble through electrostatic interaction to form a composite additive.

[0016] Preferably, the composite additive nanoparticles have an average particle size of 50 nm to 500 nm and a zeta potential of +10 mV to +50 mV.

[0017] Preferably, the composite additive can also be replaced with a modified composite additive, and the preparation method of the modified composite additive is as follows:

[0018] S1. Preparation of modified liposome core:

[0019] Lipid films containing VE and TP were prepared according to the new formula. The films were hydrated with preheated PBS containing 10% trehalose and subjected to ultrasonication and membrane extrusion to obtain glass-stable polyphenol-loaded liposomes.

[0020] S2. Construction of the cross-linked shell:

[0021] The TP / VE-Lip@Tre dispersion was mixed with the chitosan solution to form TP / VE-Lip@Tre-CS. The pH of the mixture was adjusted to 7.2, and genipin solution was added. The mixture was stirred at 37°C in the dark for 8 hours. The reaction solution was then dialyzed against deionized water for 24 hours through a dialysis bag to remove small molecule impurities and obtain the cross-linked product.

[0022] S3. Assembly of the multi-layer protective shell:

[0023] The TP / VE-Lip@Tre-CS-Gn dispersion was mixed with an equal volume of 0.1% pectin solution, stirred at room temperature for 30 minutes, centrifuged and washed to remove free pectin, and resuspended in buffer solution. The above particle dispersion was then mixed with an equal volume of 0.1% (w / v) ε-polylysine solution, stirred at room temperature for 30 minutes, centrifuged and washed, and resuspended in sterile water to obtain the final product, modified composite additive. This product was then freeze-dried to obtain a solid powder.

[0024] Preferably, the modified composite additive nanoparticles contain a glass-forming agent, which is at least one of trehalose, sorbitol, or sucrose, and the outermost layer of the modified composite additive nanoparticles also contains at least one polymer film coated by electrostatic layer-by-layer self-assembly technology.

[0025] A method for preparing fennel essential oil microcapsules includes the following steps:

[0026] S1. Dissolve the protein and the first polysaccharide in water, adjust the pH to 6.0-9.0, and carry out the Maillard reaction to obtain a composite wall material solution;

[0027] S2. Mix fennel essential oil with the composite wall material solution and emulsify to form a primary emulsion;

[0028] S3. The primary emulsion is mixed with an aqueous solution containing the second polysaccharide, and a microcapsule suspension is formed by electrostatic deposition.

[0029] S4. The microcapsule suspension is solidified, separated, and dried to obtain the fennel essential oil microcapsules.

[0030] This invention provides a microcapsule for fennel essential oil and its preparation method. It offers the following advantages: By constructing a microcapsule system with the synergistic effect of Maillard reaction composite wall material and "vitrification-crosslinking-multilayer encapsulation" modified composite nanoparticles, this invention produces several significant benefits: First, it achieves over 90% efficient encapsulation of fennel essential oil, and through a synergistic active antioxidant network and multilayered dense physical barriers, its oxidative stability and shelf life are fundamentally extended. Second, it endows the product with excellent physical stability, intelligent sustained-release properties, and excellent thermal processing tolerance, resulting in a longer-lasting flavor in the final product. Finally, the system uses natural raw materials, has a controllable process, and the composite additives can be pre-cured into stable powders, facilitating large-scale production. Overall, this invention transforms fennel essential oil into a highly stable, high-load-bearing, multifunctional, and easily applicable solid ingredient, solving the industrial challenges of its volatility and easy oxidation. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] In a first embodiment, the present invention provides a technical solution:

[0033] S1. Dissolve the protein and the first polysaccharide in water, adjust the pH to 6.0-9.0, and carry out the Maillard reaction to obtain a composite wall material solution;

[0034] S2. Mix fennel essential oil with the composite wall material solution and emulsify to form a primary emulsion;

[0035] S3. Prepare the composite additive by weighing 100mg of soybean lecithin, 20mg of cholesterol, and 30mg of tea polyphenols, dissolving them together in a 10mL mixture of anhydrous ethanol and chloroform, placing the mixture in a round-bottom flask, connecting the flask to a rotary evaporator, and evaporating under reduced pressure at a water bath of 40℃ for 60-90 minutes until a uniform and dry lipid-polyphenol composite film is formed on the flask wall. Continue to dry under reduced pressure for 2 hours to ensure complete removal of organic solvent residues.

[0036] S4. Add 10 mL of preheated phosphate buffer to the above-mentioned dried film, and hydrate it at 200 rpm for 60 minutes at the same temperature to completely detach and disperse the film, forming a milky white suspension containing large-diameter multi-compartment liposomes.

[0037] S5. The above crude liposome suspension is first treated with a probe-type ultrasonic cell disruptor under ice-water bath conditions to obtain liposomes with smaller particle size. In order to further obtain liposomes with uniform particle size, the ultrasonic liquid is passed through a liposome extruder and then through polycarbonate membranes with pore sizes of 400 nm and 200 nm in sequence, and each membrane is extruded 10-15 times to obtain a small single-chamber liposome dispersion with a particle size distribution of 150-250 nm and encapsulating tea polyphenols.

[0038] S6. Prepare a 1 mg / mL chitosan solution: Dissolve CS in a 1% acetic acid solution and stir magnetically overnight. Adjust the pH to 5.5 with NaOH. Under magnetic stirring, slowly add the dispersion of small single-chamber liposomes encapsulated with tea polyphenols to an equal volume of CS solution. Continue stirring and reacting at room temperature for 60 minutes. During the reaction, the negatively charged liposomes and the positively charged chitosan self-assemble through electrostatic interaction to form a composite additive.

[0039] S7. The primary emulsion in S2 is mixed with an aqueous solution containing the above-mentioned composite additives, and a microcapsule suspension is formed by electrostatic deposition.

[0040] S8. The microcapsule suspension is solidified, separated, and dried to obtain the fennel essential oil microcapsules.

[0041] In the second embodiment, the present invention provides a technical solution: based on the first embodiment, S1, the protein and the first polysaccharide are dissolved in water, the pH is adjusted to 6.0-9.0, and the Maillard reaction is carried out to obtain a composite wall material solution;

[0042] S2. Mix fennel essential oil with the composite wall material solution and emulsify to form a primary emulsion;

[0043] S3. Prepare modified composite additives, prepare lipid films containing VE and TP according to the new formula, hydrate the films with preheated PBS containing 10% trehalose, and perform ultrasonication and membrane extrusion to obtain glass-stable polyphenol-loaded liposomes.

[0044] S4. Mix the TP / VE-Lip@Tre dispersion with the chitosan solution to form TP / VE-Lip@Tre-CS. Adjust the pH of the mixture to 7.2, add genipin solution, and stir at 37°C in the dark for 8 hours. Dialyze the reaction solution to deionized water through a dialysis bag for 24 hours to remove small molecule impurities and obtain the cross-linked product.

[0045] S5. Mix the TP / VE-Lip@Tre-CS-Gn dispersion with an equal volume of 0.1% pectin solution, stir at room temperature for 30 minutes, centrifuge and wash to remove free pectin, resuspend in buffer solution, mix the above particle dispersion with an equal volume of 0.1% (w / v) ε-polylysine solution, stir at room temperature for 30 minutes, centrifuge and wash, resuspend in sterile water to obtain the final product modified composite additive, freeze-dry to obtain solid powder;

[0046] S6. The primary emulsion in S2 is mixed with an aqueous solution containing the above-mentioned modified composite additives, and a microcapsule suspension is formed by electrostatic deposition.

[0047] S7. The microcapsule suspension is solidified, separated, and dried to obtain the fennel essential oil microcapsules.

[0048] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A microcapsule of fennel essential oil, characterized in that, The material includes a core and a wall enclosing the core. The core contains fennel essential oil, and the wall contains a protein and a first polysaccharide. The protein and the first polysaccharide are cross-linked via a Maillard reaction to form a composite wall material.

2. The fennel essential oil microcapsule according to claim 1, characterized in that: The protein is selected from at least one of whey protein isolate, soy protein isolate, pea protein, and zein.

3. The fennel essential oil microcapsule according to claim 1, characterized in that: The first polysaccharide is selected from at least one of gum arabic, pectin, chitosan, and sodium carboxymethyl cellulose.

4. The fennel essential oil microcapsule according to claim 1, characterized in that: The capsule wall also contains a composite additive, which is prepared by the following method: S1. Preparation of lipid films: Accurately weigh 100mg of soybean lecithin, 20mg of cholesterol, and 30mg of tea polyphenols, and dissolve them together in a 10mL mixture of anhydrous ethanol and chloroform. Place the mixture in a round-bottom flask, connect the flask to a rotary evaporator, and evaporate under reduced pressure at a water bath of 40℃ for 60-90 minutes until a uniform and dry lipid-polyphenol composite film is formed on the flask wall. Continue drying under reduced pressure for 2 hours to ensure complete removal of organic solvent residues. S2, Liposome hydration and primary dispersion: Add 10 mL of preheated phosphate buffer to the above-mentioned dried film, and hydrate it by rotating at 200 rpm for 60 minutes at the same temperature to completely detach and disperse the film, forming a milky white suspension containing large-diameter multi-compartment liposomes. S3. Liposome homogenization and refinement: The above crude liposome suspension was first treated with a probe-type ultrasonic cell disruptor under ice-water bath conditions to obtain liposomes with smaller particle size. In order to further obtain liposomes with uniform particle size, the ultrasonicated liquid was passed through a liposome extruder and then through polycarbonate membranes with pore sizes of 400 nm and 200 nm in sequence, extruded 10-15 times each, to obtain a small single-chamber liposome dispersion with a particle size distribution of 150-250 nm and encapsulated tea polyphenols. S4, cationic polymer coating: To prepare a 1 mg / mL chitosan solution: Dissolve CS in a 1% acetic acid solution and stir magnetically overnight. Adjust the pH to 5.5 with NaOH. Under magnetic stirring, slowly add the dispersion of small single-chamber liposomes encapsulated with tea polyphenols to an equal volume of CS solution. Continue stirring at room temperature for 60 minutes. During the reaction, the negatively charged liposomes and the positively charged chitosan self-assemble through electrostatic interaction to form a composite additive.

5. The fennel essential oil microcapsule according to claim 4, characterized in that: The composite additive nanoparticles have an average particle size of 50 nm to 500 nm and a zeta potential of +10 mV to +50 mV.

6. The fennel essential oil microcapsule according to claim 4, characterized in that: The composite additive can also be replaced with a modified composite additive, and the preparation method of the modified composite additive is as follows: S1. Preparation of modified liposome core: Lipid films containing VE and TP were prepared according to the new formula. The films were hydrated with preheated PBS containing 10% trehalose and subjected to ultrasonication and membrane extrusion to obtain glass-stable polyphenol-loaded liposomes. S2. Construction of the cross-linked shell: The TP / VE-Lip@Tre dispersion was mixed with the chitosan solution to form TP / VE-Lip@Tre-CS. The pH of the mixture was adjusted to 7.2, and genipin solution was added. The mixture was stirred at 37°C in the dark for 8 hours. The reaction solution was then dialyzed against deionized water for 24 hours through a dialysis bag to remove small molecule impurities and obtain the cross-linked product. S3. Assembly of the multi-layer protective shell: The TP / VE-Lip@Tre-CS-Gn dispersion was mixed with an equal volume of 0.1% pectin solution, stirred at room temperature for 30 minutes, centrifuged and washed to remove free pectin, and resuspended in buffer solution. The above particle dispersion was then mixed with an equal volume of 0.1% (w / v) ε-polylysine solution, stirred at room temperature for 30 minutes, centrifuged and washed, and resuspended in sterile water to obtain the final product, modified composite additive. This product was then freeze-dried to obtain a solid powder.

7. The fennel essential oil microcapsule according to claim 6, characterized in that: The modified composite additive nanoparticles contain a glass-forming agent, which is at least one of trehalose, sorbitol, or sucrose. The outermost layer of the modified composite additive nanoparticles also contains at least one polymer film coated by electrostatic layer-by-layer self-assembly technology.

8. The method for preparing fennel essential oil microcapsules according to claim 1, characterized in that, Includes the following steps: S1. Dissolve the protein and the first polysaccharide in water, adjust the pH to 6.0-9.0, and carry out the Maillard reaction to obtain a composite wall material solution; S2. Mix fennel essential oil with the composite wall material solution and emulsify to form a primary emulsion; S3. The primary emulsion is mixed with an aqueous solution containing the second polysaccharide, and a microcapsule suspension is formed by electrostatic deposition. S4. The microcapsule suspension is solidified, separated, and dried to obtain the fennel essential oil microcapsules.