Preparation method of microfluidic-based aroma slow-release microcapsules and application thereof in cigar maintenance

Abstract

The application discloses a preparation method of aroma slow-release microcapsules based on microfluidics and application of the aroma slow-release microcapsules in cigar maintenance. The preparation method of the application utilizes microfluidic technology, controls the structural size of a microfluidic device, the flow and components of an oil-phase core liquid and a water-phase shell liquid, and forms core-shell structure microcapsules with different sizes, wall thicknesses and strengths at the outlet of the microfluidic device; the core-shell structure microcapsules undergo filtration, twice solidification, rotating drum drying and tray drying, and finally obtain the microcapsules capable of slow-releasing aroma. Different concentrations of the microcapsules are prepared by changing the addition amount of the coated aroma medium, and different flavors of the microcapsules are prepared by changing the types of the aroma medium. The aroma slow-release microcapsules are applied to cover and embed cigars, and cigar maintenance and aging are realized. The concentration of the cigar flavor, the cigar maintenance and aging speed can be regulated by changing the number of the microcapsules or selecting different concentrations of the microcapsules. The flavor type of the cigar can be regulated by selecting different flavors of the microcapsules.

Description

Preparation method of aroma sustained-release microcapsules based on microfluidics and their application in cigar maintenance Technical Field

[0001] This invention relates to the field of cigar production and maintenance technology, specifically to a method for preparing aroma-slow-release microcapsules based on microfluidics and their application in cigar maintenance. Background Technology

[0002] Cigar aging and storage, also known as tobacco leaf maturation or "aging," is a slow and gentle fermentation process that eliminates off-flavors, reduces harshness, and improves the aftertaste. It is a crucial step in improving the quality of cigar tobacco leaves. The aging process has a positive impact on the aroma, off-flavors, harshness, and aftertaste of cigars.

[0003] The conventional method involves using wooden containers for aging and maturation. The principle is that the cigars absorb the volatile components of the wood, thus completing the aging process. Specifically, cigars are placed in wooden cabinets (such as cedar or fir) at a controlled temperature and humidity, sealed, and stored for a certain period. However, this method has the following problems: the wood is expensive and environmentally unfriendly; it cannot meet the need for simultaneous aging and storage of large quantities of cigars; it cannot allow the cigars to absorb aromas other than woody notes; and the flavor improvement is limited to increasing the aging time, resulting in a single flavor control method. Other common practices, such as directly spraying aroma enhancers onto the cigars, not only fail to control the intensity of the aroma but also contaminate the cigars, leading to a decline in sensory quality.

[0004] Microencapsulation is a micro-packaging technology for storing solids, liquids, and gases. It involves completely encapsulating a target substance (core or inner phase) with various natural or synthetic polymer compounds (wall or outer phase). The encapsulated component's function is then gradually revealed through external stimuli or sustained-release mechanisms, or the capsule wall protects the core material. Microcapsules can generally be made into free-flowing powders or suspensions, releasing the target substance through mechanical means, pressure, friction, diffusion, capsule wall dissolution, and biodegradation. In terms of application, microcapsules can be categorized into sustained-release, thermosensitive, pressure-sensitive, and photosensitizing types. Currently, microencapsulation technology is used in food, pharmaceuticals, animal feed, and inks. Summary of the Invention

[0005] To address the shortcomings of existing cigar aging and conditioning methods, this invention provides a method for preparing aroma-sustaining microcapsules based on microfluidics and their application in cigar conditioning; comprising the following steps:

[0006] 1) Mix the solvent oil, oil-soluble fragrance, plant essential oil and oil-soluble pigment and stir evenly to obtain the oil phase stock solution;

[0007] 2) The original oil phase solution is then added dropwise to the solvent oil to obtain the oil phase core solution;

[0008] 3) Add microcapsule shell material and plasticizer to a sodium alginate solution with a mass percentage of 1% to 2% to prepare an aqueous shell liquid;

[0009] 4) Pump the oil-phase core fluid and the aqueous-phase shell fluid into the microfluidic device at a volume flow ratio of 1:2 to 4 to obtain core-shell structured microcapsules;

[0010] 5) Drop the core-shell structured microcapsules into the initial coagulation solution for 5-10 minutes, and filter to obtain the aroma wet microcapsules;

[0011] 6) Pour the aroma wet microcapsules into the secondary coagulation solution, filter and dry after 20-40 minutes to obtain aroma sustained-release microcapsules.

[0012] As a preferred embodiment of the present invention, the oil phase stock solution obtained in step 1) includes 9 to 11 parts by mass of solvent oil, 2 to 3 parts by mass of oil-soluble fragrance, 2 to 3 parts by mass of plant essential oil, and 0.2 to 0.4 parts by mass of oil-soluble pigment.

[0013] In a preferred embodiment of the present invention, step 2) specifically involves adding 3-10 parts by weight of oil phase stock solution to 90-97 parts by weight of solvent oil. More preferably, the oil phase stock solution added in step 2 can be an oil phase stock solution with a different flavor.

[0014] As a preferred embodiment of the present invention, the mass of the microcapsule shell material added in step 3) is 0.5% to 2% of the mass of the aqueous shell liquid; the mass ratio of the added plasticizer to the microcapsule shell material is 1:1 to 2.

[0015] As a preferred embodiment of the present invention, in step 4), the microfluidic device includes an inner tube and an outer tube; the outer tube wraps around the outside of the inner tube; the inlet end of the inner tube is opened at the rear end of the microfluidic device; the inlet end of the outer tube is a hole opened on the side of the microfluidic device; the inlet end of the inner tube and the outlet end of the outer tube are opened at the front end of the microfluidic device, and the outlet end of the outer tube extends 1-2 mm beyond the outlet end of the inner tube; the outer tube is used for flowing aqueous shell liquid, and the inner tube is used for flowing oil core liquid.

[0016] As a preferred embodiment of the present invention, the inner tube of the microfluidic device has an inner diameter of 0.4-0.5 mm and a wall thickness of 0.2-0.3 mm; the outer tube has an inner diameter of 1.2-2 mm and a wall thickness of 0.4-0.6 mm.

[0017] As a preferred embodiment of the present invention, the primary coagulation solution in step 5) is a 5wt%-15wt% calcium chloride aqueous solution; the secondary coagulation solution in step 6) is a 5wt%-10wt% calcium chloride aqueous solution with pH=4-7.

[0018] This invention also provides an application of the above-mentioned aroma-sustaining microcapsules in cigar preservation, comprising the following steps:

[0019] a) Place the cigars inside the curing cabinet and maintain the relative humidity of the environment inside the cabinet at 68%–75% and the ambient temperature at 16℃–20℃.

[0020] b) Cover and embed the cigars with aroma-slow-release microcapsules, and then seal them in a cigar preservation cabinet for preservation.

[0021] The beneficial effects that this invention can produce include:

[0022] (1) Using aroma-slow-release microcapsules to regulate cigar maintenance: By changing parameters such as the wall material, wall thickness, and coverage of the slow-release microcapsules, the aroma-slow-release effect can be controlled, and the cigar aroma retention time can be extended; by using a variety of slow-release microcapsules with different strengths, flavors, quantities, and sizes, the flavor type and strength of the cigar can be controlled.

[0023] (1) By changing the amount of oil phase stock solution added, oil phase core liquids with different concentrations of aroma medium components can be obtained, and microcapsules with different aroma intensity can be prepared. The intensity of the aroma can be reflected by the color of the microcapsules. Cigars with different aroma intensity can be maintained by microcapsules with different aroma intensity to obtain cigars with different flavor intensity.

[0024] (2) When the number of cigars is fixed, changing the number of microcapsules in the curing cabinet can produce cigars with different flavor strengths. Simply increasing the number of aroma-releasing microcapsules can make the cigar flavor more mellow; this can be achieved by increasing the number of aroma-releasing microcapsules when curing a large number of cigars.

[0025] (3) By changing the types of oil-soluble flavorings and plant essential oils, i.e. the types of aroma media, microcapsules with different aroma types are prepared, and then the cigars are wrapped and covered for preservation treatment to regulate the flavor type of the cigars.

[0026] (4) The present invention is no longer limited to using wooden curing cabinets, and the microcapsules themselves can also prevent cigars from being contaminated by the encapsulation and wrapping of the oil phase core liquid.

[0027] (5) The method used in this invention makes cigar maintenance easy to operate and control. Attached Figure Description

[0028] Figure 1 is a flowchart of the process for preparing aroma sustained-release microcapsules of the present invention;

[0029] Figure 2 is a diagram of the microfluidic device provided by the present invention;

[0030] Figure 3 is a schematic diagram of the microcapsule preservation method for cigars provided by the present invention.

[0031] Legend: 1. Inner tube; 2. Outer tube. Detailed Implementation

[0032] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0033] The preparation method of this invention utilizes microfluidics technology. By controlling the structural dimensions of the microfluidic device and the flow rates and compositions of the oil-phase core liquid and the aqueous-phase shell liquid, core-shell microcapsules of different sizes, wall thicknesses, and strengths are formed at the outlet of the microfluidic device. These core-shell microcapsules undergo filtration, two coagulation processes, rotary drying, and tray drying to ultimately obtain microcapsules capable of sustained-release aroma. Changing the amount of aroma medium added prepares microcapsules of varying concentrations; changing the type of aroma medium prepares microcapsules with different flavors.

[0034] As shown in Figure 1, aroma-release microcapsules were prepared using microfluidic technology. The specific microfluidic device, as shown in Figure 2, was fabricated using 3D printing. An oil-phase core liquid and an aqueous-phase shell liquid were pumped into the two-phase channel of the microfluidic device at a specific two-phase flow ratio, forming core-shell structured microcapsules at the device outlet. These microcapsules were then dropped into the initial coagulation solution and removed after 5-10 minutes to obtain initially formed wet aroma microcapsules. A secondary coagulation solution was then poured in, and the microcapsules were stabilized and solidified again. After 30 minutes, the microcapsules were filtered and dried to obtain dry, sustained-release microcapsules. The drying process involved rotary drying at a speed of 5-10 r / min, a drying temperature of 20-36℃, and a duration of 2-4 hours, followed by tray drying for 2-4 hours to obtain dry microcapsules.

[0035] The inner tube of the microfluidic device has an inner diameter of 0.4–0.6 mm and a wall thickness of 0.2–0.4 mm; the outer tube has an inner diameter of 1.2–2 mm and a wall thickness of 0.4–0.6 mm; the outer tube extends 1.0–2 mm beyond the inner tube.

[0036] The flow rate ratio of the oil phase core fluid to the water phase shell fluid is 1:(2.0~4), preferably 1:3.

[0037] The preparation method of the oil-phase core liquid is as follows: Prepare an oil-phase stock solution by mixing and stirring 9-11 parts by weight of solvent oil, 2-3 parts by weight of oil-soluble fragrance, 2-3 parts by weight of plant essential oil, and 0.2-0.4 parts by weight of oil-soluble pigment. Then, dropwise add the oil-phase stock solution to the solvent oil to prepare the oil-phase core liquid. The proportion of the oil-phase stock solution is 3%-10% of the oil-phase core liquid. During the process of adding the oil-phase stock solution to the solvent oil to prepare the oil-phase core liquid, multiple oil-phase stock solutions with different flavors can be added.

[0038] The solvent oil is one or more of the following: cosmetic oil-based solvent raw materials or food-grade oil-based solvent raw materials; cosmetic oil-based solvent raw materials include caprylic / capric triglyceride, dioctyl carbonate, isononyl isononyl ether, polydimethylsiloxane, etc.; and food-grade oil-based solvent raw materials include olive oil, peanut oil, etc.

[0039] Oil-soluble flavorings include at least one of the following categories: cedarwood flavoring, coffee flavoring, vanilla flavoring, honey flavoring, chocolate flavoring, almond flavoring, whiskey flavoring, strawberry flavoring, rose flavoring, and peppermint flavoring;

[0040] The plant essential oil is at least one of the following: rose essential oil, peppermint essential oil, lavender essential oil, tea tree essential oil, ginger root essential oil, rosemary essential oil, sandalwood essential oil, cinnamon essential oil, grapefruit essential oil, pomegranate essential oil, etc.

[0041] Oil-soluble pigments can be in a variety of colors.

[0042] The aqueous shell liquid is a sodium alginate solution with a mass fraction of 1-2%, compounded with other commonly used microcapsule shell materials with a mass fraction of 0.5-2%, and a plasticizer is added. The mass ratio of plasticizer to shell material can be selected as 1:1-2, preferably 1:1.6. Preferably, the plasticizer is glycerol.

[0043] The primary coagulation solution is a calcium chloride aqueous solution with a mass fraction of 5%-25%; the secondary coagulation solution is a calcium chloride aqueous solution with a pH of 4-7 and a mass fraction of 5%-15%. Core-shell microcapsules are dripped into the coagulation bath, where the sodium alginate on the outer shell cross-links with calcium ions in the coagulation bath to form a calcium alginate network, creating aroma-releasing microcapsules with mechanical strength.

[0044] As shown in Figure 3, the aroma-releasing microcapsules prepared according to this invention are used to coat and encapsulate cigars, achieving cigar aging and preservation. Changing the number of microcapsules or selecting microcapsules of different concentrations can control the intensity of the cigar's flavor and the speed of aging and preservation. Selecting microcapsules with different flavors can control the flavor profile of the cigar.

[0045] Includes the following steps:

[0046] Step 1: Place the cigars inside the curing cabinet and maintain the relative humidity of the environment inside the cabinet at 68% to 75% and the ambient temperature at 16°C to 20°C.

[0047] Step 2: Place a certain number of aroma-releasing microcapsules with a specific fragrance into the cigar, cover and embed them, seal the cigar cabinet, and complete the aging process, as shown in Figure 1.

[0048] In step 1, the number of cigars can be any, only limited by the size of the curing cabinet. This eliminates the problem of using only 70% of the cabinet's volume due to the impact of too many cigars on the aging process, allowing for the full utilization of the curing cabinet's volume.

[0049] In step 1, the curing cabinet can be made of any material, such as wood, plastic, or iron.

[0050] Example 1: Coffee-flavored slow-release microcapsules preserve coffee-flavored cigars.

[0051] The method of the present invention is used to prepare coffee-flavored cigars. The specific steps are as follows: five cigars are placed in the internal cavity of a curing cabinet, and the relative humidity of the cavity is maintained at 70% and the ambient temperature is 18°C; 1,000 coffee-flavored microcapsules are placed in the cavity, covering and embedding the cigars; the curing cabinet is sealed and the cigars are cured and allowed to mature.

[0052] Preparation of oil phase core fluid: First, take 10g of caprylic / capric triglyceride, 5g of oil-soluble coffee flavoring, and 0.25g of pigment red to prepare the oil phase stock solution; after stirring evenly, take 6g of the stock solution and add it to 96g of caprylic / capric triglyceride to obtain the oil phase core fluid.

[0053] Preparation of the aqueous shell solution: Take 98g of deionized water and add 2g of sodium alginate to obtain a 2% sodium alginate solution. Then add 1g of plasticizer and 1g of microcapsule shell material to the sodium alginate solution;

[0054] The coffee-flavored sustained-release microcapsules were fabricated using microfluidic devices. As shown in Figure 2, the inner tube 1 carries an oil-phase core liquid at a flow rate of 0.22 ml / min, while the outer tube 2 carries an aqueous-phase shell liquid at a flow rate of 0.66 ml / min. The two are flowed at a 1:3 ratio, forming core-shell microcapsules at the outlet. These microcapsules are then dripped into a coagulation solution, where sodium alginate and calcium chloride cross-link. After 10 minutes, the microcapsules are filtered out and placed back into the secondary coagulation solution. After 30 minutes, they are filtered out again. The microcapsules are then placed in a rotary dryer and dried at 6 rpm at 28°C for 4 hours. Afterward, they are dried on a tray for another 4 hours, ultimately yielding coffee-flavored dry microcapsules with mechanical strength, suitable for cigar preservation.

[0055] The primary coagulation solution is a 6% calcium chloride solution; the secondary coagulation solution is a 6% calcium chloride solution, and its pH is adjusted to 5 with hydrochloric acid.

[0056] Example 2: Cigars with varying degrees of coffee flavor were produced by using microcapsules.

[0057] Comparative Example 1 for the preparation of the oil-phase core liquid: 9g of the oil-phase stock solution was added to 96g of caprylic / capric triglyceride to obtain the oil-phase core liquid. The specific curing steps, preparation of the oil-phase stock solution, preparation of the aqueous shell liquid, and preparation of the coagulation solution and microcapsules were the same as in Example 1, resulting in sustained-release microcapsules with a stronger coffee flavor than those in Example 1. Then, 1000 of these strong-flavored microcapsules were placed in a curing cabinet of the same specifications, environmental conditions, and number of cigars as in Example 1, covering and embedding the cigars, and curing for the same time, resulting in coffee-flavored cigars with a richer flavor than those in Example 1.

[0058] Example 3.: Cedar-flavored slow-release microcapsules preserve cedar-flavored cigars.

[0059] Preparation of oil phase core fluid: First, take 10g of caprylic / capric triglyceride, 6g of cedarwood essential oil, and 0.28g of pigment blue to prepare the oil phase stock solution; after stirring evenly, take 6g of the stock solution and add it to 96g of caprylic / capric triglyceride to obtain the oil phase core fluid.

[0060] The preparation of the aqueous shell liquid, the coagulation solution, and the microcapsules are the same as in Example 1, resulting in cedar-flavored sustained-release microcapsules. Following the same steps as in Example 1 for microcapsule-preserved cigars, cedar-flavored cigars are obtained.

[0061] Example 4: Fabrication of Microfluidic Devices

[0062] Single-channel or multi-channel microfluidic devices were designed using Solidworks 3D modeling software and manufactured using photosensitive resin material via photopolymerization 3D printing. The key dimensions are as follows: inner tube inner diameter 0.5mm, wall thickness 0.2mm; outer tube inner diameter 1.2mm, wall thickness 0.25mm; outer tube protruding 1.2mm from the inner tube. Hydrophobic treatment of the tube openings is required when using this device.

[0063] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. The application of a sustained-release aroma microcapsule in cigar care, characterized in that, Includes the following steps: a) Place the cigars inside the cavity of the curing cabinet and maintain the relative humidity of the cavity at 68%–75% and the ambient temperature at 16℃–20℃; b) Cover and encapsulate the cigars with aroma-slow-release microcapsules, seal the curing cabinet, and cure the cigars; the aroma-slow-release microcapsules are based on microfluidic control. The preparation method includes the following steps: 1) Mixing and stirring solvent oil, oil-soluble fragrance, plant essential oil and oil-soluble pigment to obtain an oil phase stock solution; the oil phase stock solution obtained in step 1) includes 9-11 parts by mass of solvent oil, 2-3 parts by mass of oil-soluble fragrance, 2-3 parts by mass of plant essential oil and 0.2-0.4 parts by mass of oil-soluble pigment; 2) Adding the oil phase stock solution dropwise to solvent oil to obtain an oil phase core liquid; specifically, step 2) involves adding 3-10 parts by mass of oil phase stock solution to 90-97 parts by mass of solvent oil; 3) Adding microcapsule shell material and plasticizer to a sodium alginate solution with a mass percentage of 1%-2% to prepare an aqueous phase outer shell liquid; the mass of the microcapsule shell material added in step 3) is 0.5%-2% of the mass of the aqueous phase outer shell liquid; the mass ratio of the added plasticizer to the microcapsule shell material is 1:1-2; 4) Mixing the oil phase core liquid and the aqueous phase outer shell liquid at a ratio of 1: A volumetric flow rate of 2-4 is pumped into a microfluidic device to obtain core-shell microcapsules; the microfluidic device includes an inner tube and an outer tube; the outer tube is used for the flow of the aqueous shell liquid, and the inner tube is used for the flow of the oil core liquid; the inner diameter of the inner tube of the microfluidic device is 0.4-0.5 mm, and the wall thickness is 0.2-0.3 mm; the inner diameter of the outer tube is 1.2-2 mm, and the wall thickness is 0.4-0.6 mm; 5) the core-shell microcapsules are dripped into the primary coagulation solution, and filtered after 5-10 min to obtain aroma wet microcapsules; 6) the aroma wet microcapsules are poured into the secondary coagulation solution, filtered and dried after 20-40 min to obtain aroma sustained-release microcapsules; the primary coagulation solution in step 5) is a 5 wt%-15 wt% calcium chloride aqueous solution; the secondary coagulation solution in step 6) is a 5 wt%-10 wt% calcium chloride aqueous solution with pH=4-7.

2. The application according to claim 1, characterized in that, In step 4), the outer tube is wrapped around the outside of the inner tube; the inlet end of the inner tube is opened at the rear end of the microfluidic device; the inlet end of the outer tube is a hole opened on the side of the microfluidic device; the inlet end of the inner tube and the outlet end of the outer tube are both opened at the front end of the microfluidic device, and the outlet end of the outer tube extends 1~2 mm beyond the outlet end of the inner tube.

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