Preparation and application of pyrazine cyclodextrin sustained-release microcapsule

Abstract

The invention belongs to the technical field of analysis and detection of tobacco flavors and fragrances, and particularly relates to preparation and application of pyrazine cyclodextrin sustained-release microcapsules. The preparation process comprises the following steps: preparing cyclodextrin dispersion liquid from cyclodextrin; adding an ethanol solution of a pyrazine compound into the cyclodextrin dispersion liquid, and carrying out single-focusing microwave treatment to obtain a microcapsule mixed liquid; putting the microcapsule mixed solution into a heat preservation box for refrigeration and aging; filtering the refrigerated microcapsule mixed solution under reduced pressure to obtain a precipitate; and washing the precipitate with methanol, and drying to obtain the pyrazine cyclodextrin sustained-release microcapsule. When the pyrazine cyclodextrin sustained-release microcapsule prepared by the technical scheme is applied to heating cigarettes, the aroma amount of smoke can be improved, and the mouth-by-mouth inconsistency of sensory quality in the smoking process is reduced. And the microcapsule is simple to synthesize and prepare, easy to operate and low in cost.

Description

Technical Field

[0001] The invention belongs to the technical field of analysis and detection of tobacco flavors and fragrances, and specifically relates to the preparation and application of pyrazine cyclodextrin sustained-release microcapsules. Background Art

[0002] Heated cigarettes are increasingly valued by the tobacco industry, and major multinational tobacco companies have launched heated tobacco products. Compared with traditional cigarettes, a notable feature of heated cigarettes is that they greatly reduce the production of harmful substances. The characteristics of heated cigarettes in terms of raw materials and heating methods determine their smoke generation and flavor substance cracking and release mechanisms, which often result in shortcomings such as insufficient flavor and smoke production, and poor consistency from puff to puff. Since the electric heating method of heated cigarettes is different from the combustion method of traditional cigarettes, the substances delivered from puff to puff during the smoking process are different from those of traditional cigarettes. The amount of aroma and smoke in the smoke decreases as the number of puffs increases, resulting in inconsistent sensory quality and smoke volume from puff to puff during the smoking process, making it difficult to achieve the satisfaction brought by traditional cigarettes.

[0003] Nitrogen heterocyclic aroma substances are an important component of the aroma components of traditional cigarette smoke. They generally have aromas such as baking and nuts, are coordinated with the smoke aroma, and are closely related to the aroma richness and smoke concentration. When traditional cigarettes are burned and smoked, most of the substances in the tobacco are cracked at a temperature above 600°C, and complex chemical reactions occur. Nitrogen heterocyclic aroma substances can be well generated and released. However, the heating temperature of heated cigarettes is about 300°C. Although the generation of harmful substances is greatly reduced, a lot of aroma substances are also lost, especially the generation and release of important nitrogen heterocyclic aroma substances in traditional cigarette smoke are significantly reduced. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation and application of pyrazine cyclodextrin sustained-release microcapsules, so as to solve the problems existing in the above-mentioned background technology by improving the sustained-release performance and aroma persistence of pyrazine heterocyclic flavors in heated cigarettes.

[0005] To achieve the above objectives, this application is implemented through the following technical solutions:

[0006] A preparation method of pyrazine cyclodextrin sustained-release microcapsules comprises the following steps:

[0007] S1. Preparation of microcapsule wall material:

[0008] Cyclodextrin is added into deionized water, and a cyclodextrin dispersion is obtained after an ultrasonic step;

[0009] S2. Preparation of microcapsule core material:

[0010] The pyrazine compound is dissolved in ethanol;

[0011] S3, adding the ethanol solution of the pyrazine compound to the cyclodextrin dispersion, and subjecting to single-focused microwave to obtain a microcapsule mixture;

[0012] S4, placing the microcapsule mixture in a 4°C incubator for refrigeration and aging for 24-48 hours;

[0013] S5, filtering the refrigerated microcapsule mixture under reduced pressure to obtain a precipitate;

[0014] S6. The precipitate is washed 3-6 times with methanol;

[0015] S7. The washed precipitate is dried at 55-70° C. for 1.5-3 h to obtain pyrazine cyclodextrin sustained-release microcapsules.

[0016] Furthermore, the cyclodextrin is one or more of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.

[0017] Furthermore, the mass ratio of cyclodextrin to deionized water is 1:5-30.

[0018] Furthermore, the duration of the ultrasonic step is 0.5-1 h, the temperature is room temperature, and the ultrasonic frequency is 35-55 KHz.

[0019] Furthermore, the pyrazine compound is one or more of 2,3-dimethylpyrazine, 2,6-dimethylpyrazine and 3-methylpyrazine.

[0020] Furthermore, the volume ratio of the pyrazine compound to ethanol is 1:5-15.

[0021] Furthermore, the volume ratio of the ethanol solution of the pyrazine compound to the cyclodextrin dispersion is 1:10-15.

[0022] Furthermore, the reaction temperature of the single focused microwave is room temperature, the microwave reaction power is 60-80W, and the microwave reaction time is 1-2h.

[0023] Furthermore, the mass ratio of the precipitate to methanol is 1:10-15.

[0024] The beneficial effects of the present invention are:

[0025] 1. The pyrazine cyclodextrin sustained-release microcapsules prepared by the present technical solution are applied to heated cigarettes to increase the aroma of smoke and reduce the inconsistency of sensory quality from puff to puff during smoking.

[0026] 2. After the single-focused microwave treatment, the preparation of the present technical solution does not adopt the conventional treatment of using a curing agent to solidify the wall material, but is refrigerated and aged in a 4°C incubator. This treatment further thickens the wall material of the microcapsule, and at the same time, part of the cyclodextrin mixed with the core material in the capsule is cross-linked to form multiple compartments inside the microcapsule, similar to the watertight compartments on a ship, which improves the strength of the microcapsule and avoids easy breakage during the cigarette production process. It can be stored for a long time at room temperature, and during the smoking process, due to the presence of multiple compartments, the core material will not be released all at once, but gradually, so as to achieve sustained release.

[0027] The difference between this technical solution and the existing use of curing agent is that after the wall material of the microcapsule is sheared, the capsule wall reacts with the curing agent quickly to solidify, while the core material inside and the mixed part of the wall material do not contact the curing agent and are not solidified. At this time, they cannot be cross-connected with the wall part and can only be mixed in the core material. Therefore, multiple compartments cannot be formed in the microcapsule of the conventional technology. In this technical solution, because no curing agent is used, the wall material, whether the outer shell part or the part mixed with the core material, is basically solidified simultaneously. At this time, the part of the wall material mixed with the core material is connected and solidified with the wall material of the outer shell part to form a compartment.

[0028] 3. The synthesis and preparation of the microcapsules of this technical solution are simple, easy to operate and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the infrared spectrum of the sustained-release microcapsule of the present invention.

[0030] Figure 2 This is the morphology of the sustained-release capsule of the present invention.

[0031] Figure 3 This is the thermogravimetric analysis diagram of the sustained-release microcapsule of the present invention.

[0032] Figure 4 This is a release curve diagram of the sustained-release microcapsule of the present invention at 220°C. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is described in detail below through examples. The following examples are merely exemplary and can only be used to explain and illustrate the technical solution of the present invention, but cannot be construed as limiting the technical solution of the present invention.

[0034] The pyrazine cyclodextrin sustained-release microcapsules of the present application are characterized by taking β-cyclodextrin as the wall material and 2,3-dimethylpyrazine as the core material as an example. The infrared spectrum shows Figure 1 , morphology analysis see Figure 2 , thermogravimetric analysis see Figure 3 , release curve see Figure 4 .

[0035] Example 1

[0036] Application of pyrazine cyclodextrin sustained-release microcapsules to enhance the aroma volume and puff-by-puff consistency of FAST (lemon mint) heated cigarettes.

[0037] Preparation of pyrazine cyclodextrin sustained-release microcapsules:

[0038] (1) Preparation of microcapsule wall material: Cyclodextrin is added to deionized water, the mass ratio of cyclodextrin to deionized water is 1:5, and the cyclodextrin is α-cyclodextrin. After the ultrasonic step, the cyclodextrin dispersion is obtained, which is the microcapsule wall material. The ultrasonic step time is 0.5 h, the temperature is room temperature, and the ultrasonic frequency is 55 kHz.

[0039] (2) Preparation of microcapsule core material: dissolving the pyrazine compound in ethanol, wherein the pyrazine compound is 2,3-dimethylpyrazine, and the ethanol is anhydrous ethanol, and the volume ratio of the pyrazine compound to the ethanol is 1:5.

[0040] (3) Add the ethanol solution of the pyrazine compound to the cyclodextrin dispersion, the volume ratio of the ethanol solution of the pyrazine compound to the cyclodextrin dispersion is 1:10, and obtain a microcapsule mixture after single-focused microwave. The microwave reaction temperature is room temperature, the microwave reaction power is 60 W, and the microwave reaction time is 2 h.

[0041] (4) Place the microcapsule mixture in a 4°C incubator and refrigerate for 24 h.

[0042] (5) After refrigeration, the microcapsule mixture is filtered under reduced pressure to obtain a precipitate.

[0043] (6) The precipitate was washed with methanol at a mass ratio of precipitate to methanol of 1:10, and washed three times.

[0044] (7) The washed precipitate was dried to obtain pyrazine cyclodextrin sustained-release microcapsules at a drying temperature of 55 °C and a drying time of 1.5 h.

[0045] Adding pyrazine cyclodextrin sustained-release microcapsules into the filter of Fatsida (lemon mint) heated cigarettes increased the aroma by 10% and the puff-to-puff consistency by 6%.

[0046] Example 2

[0047] Application of pyrazine cyclodextrin sustained-release microcapsules to enhance the aroma volume and puff-by-puff consistency of FAST (natural smoke) heated cigarettes.

[0048] Preparation of pyrazine cyclodextrin sustained-release microcapsules:

[0049] (1) Preparation of microcapsule wall material: Cyclodextrin is added to deionized water, the mass ratio of cyclodextrin to deionized water is 1:15, and the cyclodextrin is β-cyclodextrin. After the ultrasonic step, the cyclodextrin dispersion is obtained, which is the microcapsule wall material. The ultrasonic step time is 0.7 h, the temperature is room temperature, and the ultrasonic frequency is 50 kHz.

[0050] (2) Preparation of microcapsule core material: dissolving the pyrazine compound in ethanol, wherein the pyrazine compound is 2,6-dimethylpyrazine, and the ethanol is anhydrous ethanol, and the volume ratio of the pyrazine compound to the ethanol is 1:8.

[0051] (3) Add the ethanol solution of the pyrazine compound to the cyclodextrin dispersion, the volume ratio of the ethanol solution of the pyrazine compound to the cyclodextrin dispersion is 1:12, and obtain a microcapsule mixture after single-focused microwave. The microwave reaction temperature is room temperature, the microwave reaction power is 65 W, and the microwave reaction time is 1.5 h.

[0052] (4) Place the microcapsule mixture in a 4°C incubator for 30 h.

[0053] (5) After refrigeration, the microcapsule mixture is filtered under reduced pressure to obtain a precipitate.

[0054] (6) The precipitate was washed with methanol at a mass ratio of precipitate to methanol of 1:11, and washed four times.

[0055] (7) The washed precipitate was dried to obtain pyrazine cyclodextrin sustained-release microcapsules at a drying temperature of 60 °C and a drying time of 2 h.

[0056] Adding pyrazine cyclodextrin sustained-release microcapsules into the FAST (natural smoke) heated cigarette filter increased the aroma volume by 11% and the puff-to-puff consistency by 7%.

[0057] Example 3

[0058] Application of pyrazine cyclodextrin sustained-release microcapsules to enhance the aroma volume and puff-by-puff consistency of FAST (original) heated cigarettes.

[0059] Preparation of pyrazine cyclodextrin sustained-release microcapsules:

[0060] (1) Preparation of microcapsule wall material: Cyclodextrin is added to deionized water, the mass ratio of cyclodextrin to deionized water is 1:20, and the cyclodextrin is γ-cyclodextrin. After the ultrasonic step, the cyclodextrin dispersion is obtained, which is the microcapsule wall material. The ultrasonic step time is 0.8 h, the temperature is room temperature, and the ultrasonic frequency is 45 kHz.

[0061] (2) Preparation of microcapsule core material: dissolving the pyrazine compound in ethanol, wherein the pyrazine compound is 3-methylpyrazine, and the ethanol is anhydrous ethanol, and the volume ratio of the pyrazine compound to the ethanol is 1:10.

[0062] (3) The ethanol solution of the pyrazine compound was added to the cyclodextrin dispersion, and the volume ratio of the ethanol solution of the pyrazine compound to the cyclodextrin dispersion was 1:13. After single-focused microwave treatment, a microcapsule mixture was obtained. The microwave reaction temperature was room temperature, the microwave reaction power was 70 W, and the microwave reaction time was 1.6 h.

[0063] (4) Place the microcapsule mixture in a 4°C incubator and refrigerate for 40 h.

[0064] (5) After refrigeration, the microcapsule mixture is filtered under reduced pressure to obtain a precipitate.

[0065] (6) The precipitate was washed with methanol at a mass ratio of precipitate to methanol of 1:13, and washed five times.

[0066] (7) The washed precipitate was dried to obtain pyrazine cyclodextrin sustained-release microcapsules at a drying temperature of 65 °C and a drying time of 2 h.

[0067] Adding pyrazine cyclodextrin sustained-release microcapsules into the filter of Fashda (original flavor) heated cigarettes increased the aroma volume by 9% and the puff-by-puff consistency by 4%.

[0068] Application Example 4

[0069] Application of pyrazine cyclodextrin sustained-release microcapsules to enhance the aroma volume and puff-by-puff consistency of FAST (natural smoke amber) heated cigarettes.

[0070] Preparation of pyrazine cyclodextrin sustained-release microcapsules:

[0071] (1) Preparation of microcapsule wall material: Cyclodextrin is added to deionized water, the mass ratio of cyclodextrin to deionized water is 1:30, and the cyclodextrin is α-cyclodextrin. After the ultrasonic step, the cyclodextrin dispersion is obtained, which is the microcapsule wall material. The ultrasonic step time is 1 h, the temperature is room temperature, and the ultrasonic frequency is 55 kHz.

[0072] (2) Preparation of microcapsule core material: dissolving the pyrazine compound in ethanol, wherein the pyrazine compound is 2,6-dimethylpyrazine, and the ethanol is anhydrous ethanol, and the volume ratio of the pyrazine compound to the ethanol is 1:15.

[0073] (3) Add the ethanol solution of the pyrazine compound to the cyclodextrin dispersion, the volume ratio of the ethanol solution of the pyrazine compound to the cyclodextrin dispersion is 1:15, and obtain a microcapsule mixture after single-focused microwave. The microwave reaction temperature is room temperature, the microwave reaction power is 80 W, and the microwave reaction time is 1 h.

[0074] (4) Place the microcapsule mixture in a 4°C incubator and refrigerate for 48 h.

[0075] (5) After refrigeration, the microcapsule mixture is filtered under reduced pressure to obtain a precipitate.

[0076] (6) The precipitate was washed with methanol at a mass ratio of precipitate to methanol of 1:15, and washed six times.

[0077] (7) The washed precipitate was dried to obtain pyrazine cyclodextrin sustained-release microcapsules at a drying temperature of 70 °C for 3 h.

[0078] Adding pyrazine cyclodextrin sustained-release microcapsules into the FASTA (natural smoke amber) heated cigarette filter increased the aroma volume by 8% and the puff-by-puff consistency by 5%.

[0079] The above description is only a part of the specific embodiments of the present application and is not intended to limit the present application. For relevant technical personnel in the field, the present application has various changes and variations. Any modification and replacement made within the relevant principles and implementation methods of the present application should be included in the scope of protection of the present application.

Claims

1. A preparation method for pyrazine cyclodextrin sustained-release microcapsules, characterized in that: The following steps are involved: S1. Preparation of microcapsule wall material: Adding cyclodextrin into deionized water, and obtaining a cyclodextrin dispersion after an ultrasonic step; S2. Preparation of microcapsule core material: The pyrazine compound is dissolved in ethanol; S3, adding the ethanol solution of the pyrazine compound to the cyclodextrin dispersion, and subjecting to single-focused microwave to obtain a microcapsule mixture; S4, placing the microcapsule mixture in a 4°C incubator for refrigeration and aging for 24-48 hours; S5, filtering the refrigerated microcapsule mixture under reduced pressure to obtain a precipitate; S6. The precipitate is washed 3-6 times with methanol; S7. The washed precipitate is dried at 55-70° C. for 1.5-3 h to obtain pyrazine cyclodextrin sustained-release microcapsules.

2. The preparation method of pyrazine cyclodextrin sustained-release microcapsules according to claim 1, characterized in that: The cyclodextrin is one or more of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.

3. The preparation method of pyrazine cyclodextrin sustained-release microcapsules according to claim 1, characterized in that: The mass ratio of cyclodextrin to deionized water is 1:5-30.

4. The preparation method of pyrazine cyclodextrin sustained-release microcapsules according to claim 1, characterized in that: The duration of the ultrasonic step is 0.5-1 h, the temperature is room temperature, and the ultrasonic frequency is 35-55 KHz.

5. The preparation method of pyrazine cyclodextrin sustained-release microcapsules according to claim 1, characterized in that: The pyrazine compound is one or more of 2,3-dimethylpyrazine, 2,6-dimethylpyrazine and 3-methylpyrazine.

6. The preparation method of pyrazine cyclodextrin sustained-release microcapsules according to claim 1, characterized in that: The volume ratio of the pyrazine compound to ethanol is 1:5-15.

7. The preparation method of pyrazine cyclodextrin sustained-release microcapsules according to claim 1, characterized in that: The volume ratio of the ethanol solution of the pyrazine compound to the cyclodextrin dispersion is 1:10-15.

8. The preparation method of pyrazine cyclodextrin sustained-release microcapsules according to claim 1, characterized in that: The reaction temperature of the single focused microwave is room temperature, the microwave reaction power is 60-80W, and the microwave reaction time is 1-2h.

9. The preparation method of pyrazine cyclodextrin sustained-release microcapsules according to claim 1, characterized in that: The mass ratio of precipitate to methanol is 1:10-15.

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