Preparation method of high-load dried orange peel essence slow-release microcapsules

Abstract

The application discloses a preparation method of high-load dried orange peel essence slow-release microcapsules. The method comprises the following steps: firstly, dissolving composite wall material raw materials in water to obtain an aqueous phase; secondly, mixing dried orange peel essence, vegetable oil and an emulsifier to obtain an oil phase; thirdly, dropping the oil phase into the aqueous phase to form an oil-in-water (W / O) primary emulsion, which is a core liquid; fourthly, dropping the core liquid into an outer oil phase containing a surfactant to emulsify and form a water-in-oil-in-water (W / O / W) double emulsion; fifthly, adding a forming agent solution and performing ionic crosslinking to form gel microcapsules wrapping oil droplets of the essence; and finally, separating, washing and drying to obtain the high-load dried orange peel essence slow-release microcapsules. The composite wall material raw materials are a combination of sodium alginate and pectin. The application realizes the concentration of the essence in the emulsion droplets and the physical isolation of the composite wall material raw materials through a W / O / W double emulsion template, and combines the rapid ionic gelation of the composite wall material raw materials, so that the loading rate of the essence is increased to more than 60%, which is much higher than the loading rate level of a traditional interfacial polymerization method (6.4%) and a conventional emulsion polymerization method (21.8%).

Description

Technical Field

[0001] This invention belongs to the field of tobacco additive technology, specifically relating to a method for preparing high-load tangerine peel flavor sustained-release microcapsules. Background Technology

[0002] Flavor microencapsulation technology involves encapsulating flavorings into tiny capsules using film-forming materials, achieving both protection and controlled release of the flavorings. It has wide applications in the food, daily chemical, and tobacco industries. In applications requiring sustained flavor release, microcapsules face the dual demands of high flavor loading and controlled, sustained release: on the one hand, they need a high flavor loading rate to ensure the flavor intensity of the final product; on the other hand, they need to be able to achieve slow, continuous release of the flavoring under specific conditions, rather than a burst release caused by wall material rupture.

[0003] Sodium alginate, a natural polysaccharide, possesses excellent biocompatibility and gelling properties. It can undergo ionic cross-linking with calcium ions to form a gel network, making it an ideal wall material for microcapsules. Pectin, an anionic polysaccharide, also exhibits gel-forming ability; its combination with sodium alginate can regulate the density and mechanical strength of the gel network. Studies have shown that the sodium alginate-pectin composite system can form a more compact network structure, improving the encapsulation performance and sustained-release properties of microcapsules.

[0004] However, sodium alginate-pectin composite microcapsules prepared using traditional methods suffer from low flavor loading rates, making them unsuitable for practical applications. Currently, no research has been reported on how to synergistically improve flavor loading and sustained-release performance through core-liquid formulation design. Summary of the Invention

[0005] The purpose of this invention is to provide a high-load tangerine peel flavor sustained-release microcapsule and its preparation method, so as to solve the problems of low flavor loading rate and poor sustained-release performance in the prior art, and to achieve the unity of high loading rate and excellent sustained-release performance of microcapsules.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A method for preparing high-load tangerine peel flavor sustained-release microcapsules includes the following steps:

[0008] (1) Core liquid preparation: Dissolve the composite wall material raw materials in water and adjust the pH to 4.5-5.5 to obtain the aqueous phase of the composite wall material; mix the tangerine peel flavoring with vegetable oil and emulsifier to obtain the oil phase; under high-speed shearing conditions, slowly drip the oil phase into the aqueous phase of the composite wall material to form an oil-in-water (W / O) type primary emulsion, which is the core liquid;

[0009] (2) Constructing a dual emulsion template: The core liquid obtained in step (1) is used as the inner phase and slowly added to the outer oil phase containing surfactant. Through shear emulsification, an oil-in-water (W / O / W) dual emulsion is formed.

[0010] (3) Ionic crosslinking and gelation: Add a molding agent solution to the double emulsion obtained in step (2) to cause ionic crosslinking of the composite wall material raw material in the inner aqueous phase, forming gel microcapsules that encapsulate essential oil droplets;

[0011] (4) Washing and drying: Separate and wash the gel microcapsules obtained in step (3), and dry them to obtain high-load tangerine peel flavor sustained-release microcapsules.

[0012] As a preferred technical solution, the weight percentage of each component in the preparation of the core liquid in step (1) is as follows: 0.5% to 2.5% of composite wall material raw materials, 20% to 50% of tangerine peel flavoring, 5% to 20% of vegetable oil, and 0.5% to 3% of emulsifier.

[0013] As a preferred technical solution, the composite wall material is a combination of sodium alginate and pectin, with a mass ratio of sodium alginate to pectin of 10:1 to 1:2. Low-ester pectin is used.

[0014] As a preferred technical solution, the vegetable oil is selected from at least one of soybean oil, corn oil, and sunflower seed oil; the emulsifier is selected from at least one of Tween, Span, and sucrose fatty acid esters.

[0015] As a preferred technical solution, in step (1), the high-speed shearing speed is 5000-15000 rpm and the time is 2-10 minutes.

[0016] As a preferred technical solution, in step (2), the outer oil phase is vegetable oil, and the surfactant is Tween 80 with a concentration of 1% to 5%.

[0017] As a preferred technical solution, the concentration of the molding agent solution in step (3) is 0.05-0.2 mol / L, the molding agent is a calcium salt, and the amount is 0.5%-3%; the crosslinking time is 20-40 minutes.

[0018] As a preferred technical solution, the calcium salt is selected from at least one of calcium chloride, calcium lactate, and calcium gluconate.

[0019] As a preferred technical solution, the drying conditions in step (4) are: temperature 30-50℃, relative humidity 30%-50%, and time 10-15 hours.

[0020] The core fluid prepared in step (1) of this invention is an oil-in-water (O / W) emulsion with an apparent viscosity of 5000-30000 cP at 25°C and an electrical conductivity of ≥1500 μs / cm.

[0021] The high-load tangerine peel flavor sustained-release microcapsules prepared by this invention can be applied in flavor sustained-release scenarios.

[0022] Compared with the prior art, the advantages of this invention are:

[0023] (1) By using the W / O / W dual emulsion template design, the fragrance is pre-concentrated and physically isolated in a small area. Combined with the instantaneous ion gelation of the composite wall material raw material, the fragrance loading rate was successfully increased to a maximum of 64.7%, which is much higher than the loading rate of the traditional interfacial polymerization method (6.4%) and the conventional emulsion polymerization method (21.8%).

[0024] (2) Synergistic effect of composite wall materials: The combined use of sodium alginate and pectin forms a denser three-dimensional network structure. The addition of pectin can adjust the cross-linking density and mechanical strength of the gel network and improve the encapsulation efficiency of microcapsules. Attached Figure Description

[0025] Figure 1 The bar chart shows the comparison of the microcapsule flavor loading rates of Examples 1-5 and Comparative Examples 1-2 of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0027] Example 1

[0028] A high-load tangerine peel flavor sustained-release microcapsule is prepared as follows:

[0029] (1) Preparation of core fluid

[0030] Weigh 1.5 g of composite wall material raw material (sodium alginate to pectin mass ratio 5:1, total concentration 1.5 wt%) and dissolve it in 100 mL of deionized water. Adjust the pH to 5.0 using food-grade acetic acid to obtain the aqueous phase of the composite wall material. Weigh 30 g of Guangzhou Huafang tangerine peel flavoring, 5 g of soybean oil, 1 g of Tween 80, and 0.5 g of Span 80 and mix them evenly to obtain the oil phase. Under high-speed shearing conditions of 8000 rpm, slowly drip the oil phase into the aqueous phase of the composite wall material and emulsify continuously for 5 minutes to form a stable oil-in-water (W / O) primary emulsion, which is the core liquid.

[0031] (2) Constructing a dual emulsion template

[0032] The core liquid obtained in step (1) was used as the inner phase and slowly added dropwise at a rate of 5 mL / min to the outer oil phase of soybean oil containing 3% Tween 80. The mixture was sheared and emulsified at 6000 rpm for 8 minutes to form an oil-in-water (W / O / W) double emulsion.

[0033] (3) Ionic crosslinking gelation

[0034] Slowly add an equal volume of 0.1 mol / L calcium chloride solution to the double emulsion obtained in step (2), and stir the reaction at room temperature for 25 minutes to allow the composite wall material raw materials in the inner aqueous phase to undergo ionic cross-linking and form gel microcapsules that encapsulate essential oil droplets.

[0035] (4) Washing and drying

[0036] The gel microcapsules obtained from the filtration and separation step (3) were washed three times with deionized water to remove excess calcium chloride and surfactant. The washed microcapsules were then dried in an oven at 40% relative humidity and 40°C for 12 hours to obtain the final product.

[0037] Example 2

[0038] The difference between this embodiment and embodiment 1 is that in step (1), the raw materials of the composite wall material are adjusted to a mass ratio of sodium alginate to pectin of 3:1 and a total concentration of 1.2 wt%; the amount of Guangzhou Huafang tangerine peel flavoring is adjusted to 35 g and soybean oil is adjusted to 3 g, and the rest of the steps are the same.

[0039] Example 3

[0040] The difference between this embodiment and embodiment 1 is that in step (1), the raw materials of the composite wall material are adjusted to a mass ratio of sodium alginate to pectin of 1:1 and a total concentration of 1.0 wt%; the amount of Guangzhou Huafang tangerine peel flavoring is adjusted to 40 g and soybean oil is adjusted to 2 g, and the rest of the steps are the same.

[0041] Example 4

[0042] The difference between this embodiment and embodiment 1 is that in step (1), the raw materials of the composite wall material are adjusted to a mass ratio of sodium alginate to pectin of 1:2 and a total concentration of 0.8 wt%; the amount of Guangzhou Huafang tangerine peel flavoring is adjusted to 45 g and soybean oil is adjusted to 1.5 g, and the rest of the steps are the same.

[0043] Example 5

[0044] The difference between this embodiment and embodiment 1 is that in step (1), the raw materials of the composite wall material are adjusted to a mass ratio of sodium alginate to pectin of 4:1 and a total concentration of 1.2 wt%; the amount of Guangzhou Huafang tangerine peel flavoring is adjusted to 42 g, and the other steps are the same.

[0045] Comparative Example 1 (Prepared by conventional interfacial polymerization method)

[0046] A method for preparing tangerine peel flavor microcapsules using a traditional interfacial polymerization method is as follows:

[0047] (1) Preparation of oil phase: Mix 10 g of Guangzhou Huafang tangerine peel flavoring with 2 g sebacyl chloride evenly, and dilute with 30 mL of cyclohexane to obtain an oil phase solution.

[0048] (2) Aqueous phase preparation: Dissolve 4 g hexamethylenediamine in 100 mL of deionized water, add 1% polyvinyl alcohol (PVA) as an emulsifier, stir evenly to obtain an aqueous phase solution.

[0049] (3) Emulsification and polymerization: At room temperature, the oil phase solution was slowly added dropwise to the aqueous phase solution, while high-speed shearing emulsification was performed at 10,000 rpm for 10 minutes to form an oil-in-water emulsion. After emulsification, the emulsion was transferred to a reaction vessel and reacted slowly with stirring in a 40°C water bath for 2 hours.

[0050] (4) Washing and drying: After the reaction was completed, the microcapsules were separated by centrifugation, washed three times alternately with deionized water and anhydrous ethanol, and dried under vacuum at 40°C for 12 hours to obtain the tangerine peel flavor microcapsules prepared by interfacial polymerization.

[0051] Comparative Example 2 (Conventional Emulsion Polymerization)

[0052] A tangerine peel flavor microcapsule prepared by conventional emulsion polymerization is prepared in the same way as Comparative Example 1, but the monomer is replaced with methyl methacrylate, the initiator is replaced with azobisisobutyronitrile, the polymerization temperature is adjusted to 70℃, and the polymerization time is 4 hours.

[0053] Performance Testing and Results Analysis

[0054] (a) Core fluid performance test

[0055] The performance of the core fluids prepared in Examples 1 to 5 was tested, and the results are shown in Table 1.

[0056] Table 1 Core Fluid Performance Test Results

[0057] As shown in Table 1, the apparent viscosity of the core fluid prepared in the embodiments of the present invention ranges from 5800 to 13200 cP at 25°C, and the conductivity is consistently higher than 3900 μS / cm. All core fluids are oil-in-water (O / W) emulsions. The suitable viscosity and good conductivity indicate that the core fluid forms a stable oil-in-water emulsion system, laying the foundation for high loading rates and high yields of subsequent microcapsules. A higher proportion of sodium alginate results in a higher core fluid viscosity; an increase in the pectin proportion slightly decreases the viscosity but improves the conductivity.

[0058] (II) Load Rate Comparison Test

[0059] The flavor loading rate of the microcapsules prepared in Examples 1-5 and Comparative Examples 1-2 was determined by solvent extraction-gravimetric method, and the results are as follows: Figure 1 As shown.

[0060] Depend on Figure 1 It can be seen that the loading rate of microcapsules prepared by traditional interfacial polymerization is only 6.4%, and that of conventional emulsion polymerization is 21.8%, while the loading rate of microcapsules prepared by the embodiments of the present invention is as high as 51.8% to 64.7%, of which the loading rate of Example 5 reaches 64.7%, which achieves a significant improvement in fragrance encapsulation efficiency.

[0061] (III) Effects of different sodium alginate / pectin ratios on microcapsule performance

[0062] With other conditions fixed as in Example 5, the mass ratio of sodium alginate to pectin was changed to 10:1, 5:1, 4:1, 3:1, 1:1, and 1:2 to investigate its effect on the performance of microcapsules. The results are shown in Table 2.

[0063] Table 2 Effect of sodium alginate / pectin ratio on microcapsule performance

[0064]

[0065] Table 2 shows that a higher sodium alginate ratio (10:1–4:1) results in a higher loading rate; an increase in the pectin ratio (3:1–1:1) slightly decreases the loading rate; and an excessively high pectin ratio (1:2) reduces the integrity of the pellets. Considering all factors, a sodium alginate to pectin mass ratio of 4:1–3:1 is optimal, achieving the best balance between loading rate and pellet integrity.

[0066] (iv) Effect of different cross-linking times on microcapsule performance

[0067] With other conditions fixed as in Example 5 (sodium alginate: pectin 4:1), the ionic crosslinking time was varied to 15, 20, 25, 30, and 35 minutes to investigate its effect on the performance of the microcapsules. The results are shown in Table 3.

[0068] Table 3 Effect of crosslinking time on microcapsule performance

[0069] As shown in Table 3, a crosslinking time that is too short (15 minutes) will result in insufficient crosslinking of the wall material and poor microcapsule integrity; a crosslinking time that is too long (35 minutes) will slightly decrease the loading rate, but improve the integrity of the microcapsules. Taking all factors into consideration, a crosslinking time of 20-30 minutes is optimal.

[0070] In summary, this invention successfully prepared high-load tangerine peel flavor sustained-release microcapsules using a sodium alginate-pectin composite wall material via a W / O / W dual emulsion template and ionic crosslinking technology. The flavor loading rate reached a maximum of 64.7%. The combined use of sodium alginate and pectin achieved a synergistic effect, maintaining a high loading rate. This technical solution solves the problem of low loading rate in existing microcapsules and has broad application prospects in applications requiring high-load flavor encapsulation.

[0071] The examples provided in this invention are not intended to limit the implementation of the invention. Those skilled in the art will recognize that various variations and modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all possible implementations. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of the claims.

Claims

1. A method for preparing high-load tangerine peel flavor sustained-release microcapsules, characterized in that, Includes the following steps: (1) Core liquid preparation: Dissolve the composite wall material raw materials in water and adjust the pH to 4.5-5.5 to obtain the aqueous phase of the composite wall material; mix tangerine peel flavoring with vegetable oil and emulsifier to obtain the oil phase; under high-speed shearing conditions, slowly drip the oil phase into the aqueous phase of the composite wall material to form an oil-in-water primary emulsion, which is the core liquid; (2) Constructing a dual emulsion template: The core liquid obtained in step (1) is used as the inner phase and slowly added to the outer oil phase containing surfactant. Through shear emulsification, an oil-in-water-in-oil dual emulsion is formed. (3) Ionic crosslinking and gelation: Add a molding agent solution to the double emulsion obtained in step (2) to cause ionic crosslinking of the composite wall material raw material in the inner aqueous phase, forming gel microcapsules that encapsulate essential oil droplets; (4) Washing and drying: Separate and wash the gel microcapsules obtained in step (3), and dry them to obtain high-load tangerine peel flavor sustained-release microcapsules.

2. The method for preparing high-load tangerine peel flavor sustained-release microcapsules according to claim 1, characterized in that, The weight percentages of each component in the preparation of the core liquid in step (1) are as follows: 0.5% to 2.5% of composite wall material raw materials, 20% to 50% of tangerine peel flavoring, 5% to 20% of vegetable oil, and 0.5% to 3% of emulsifier.

3. The method for preparing high-load tangerine peel flavor sustained-release microcapsules according to claim 1 or 2, characterized in that, The composite wall material is a combination of sodium alginate and pectin, with a mass ratio of sodium alginate to pectin of 10:1 to 1:

2.

4. The method for preparing high-load tangerine peel flavor sustained-release microcapsules according to claim 3, characterized in that, The pectin is a low-ester pectin.

5. The method for preparing high-load tangerine peel flavor sustained-release microcapsules according to claim 1, characterized in that, The vegetable oil is selected from at least one of soybean oil, corn oil, and sunflower seed oil; the emulsifier is selected from at least one of Tween, Span, and sucrose fatty acid esters.

6. The method for preparing high-load tangerine peel flavor sustained-release microcapsules according to claim 1, characterized in that, In step (1), the high-speed shearing speed is 5000-15000 rpm and the time is 2-10 minutes.

7. The method for preparing high-load tangerine peel flavor sustained-release microcapsules according to claim 1, characterized in that, In step (2), the outer oil phase is vegetable oil, and the surfactant is Tween 80 with a concentration of 1% to 5%.

8. The method for preparing high-load tangerine peel flavor sustained-release microcapsules according to claim 1, characterized in that, The concentration of the molding agent solution in step (3) is 0.05-0.2 mol / L, the molding agent is a calcium salt, and the amount is 0.5%-3%; the crosslinking time is 20-40 minutes.

9. The method for preparing high-load tangerine peel flavor sustained-release microcapsules according to claim 8, characterized in that, The calcium salt is selected from at least one of calcium chloride, calcium lactate, and calcium gluconate.

10. The method for preparing high-load tangerine peel flavor sustained-release microcapsules according to claim 8, characterized in that, The drying conditions for step (4) are: temperature 30-50℃, relative humidity 30%-50%, and time 10-15 hours.

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