A method for preparing a polyol-modified cyclodextrin-based emulsifier-free emulsion

Abstract

This invention discloses a method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifiers, comprising the following steps: S1, preparing polyol-modified cyclodextrin dendritic macromolecules; S2, dissolving the polyol-modified cyclodextrin dendritic macromolecules in deionized water, adding a certain amount of triacetin glycerol, and stirring evenly in a water bath; S3, adding a certain amount of oil-soluble fragrance dropwise, lowering the water bath temperature, and continuing stirring; S4, using a high-speed shear emulsifier to shear the liquid in the above steps at high speed to obtain the emulsion product. According to this invention, the problem of flavor loss caused by volatilization and oxidation of fragrances during high-temperature processing can be effectively alleviated, achieving long-term aroma retention and controllable release, providing a highly efficient and safe flavor encapsulation and delivery solution for related industries.

Description

Technical Field

[0001] This invention relates to the technical field of fragrances, and in particular to a method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifiers. Background Technology

[0002] Flavors and fragrances, as key components for enhancing the sensory experience of products, play an irreplaceable role in various industries such as food and daily chemicals. However, these substances typically have low molecular weight and high volatility, making them susceptible to degradation during processing, storage, and application due to factors such as light, heat, and oxygen, leading to aroma loss or quality decline. To address this challenge, emulsion systems, with their sustained-release properties, can regulate the release behavior of flavor compounds while protecting them, and have become a widely used technology in this field.

[0003] Cyclodextrins, due to their unique hydrophobic internal lumen and hydrophilic external surface structure, are often used as carrier materials in emulsion systems. However, traditional cyclodextrin-based emulsions typically rely on chemically synthesized emulsifiers to maintain system stability, and long-term excessive intake of emulsifiers may pose potential risks to digestion, metabolism, and the immune system. Furthermore, synthetic emulsifiers also face controversies regarding biosafety and difficulties in environmental degradation, limiting their further application. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifiers. First, cyclodextrin is converted into a dendritic macromolecular intermediate, and then a polyol is grafted onto it via esterification to obtain a polyol-modified cyclodextrin dendritic macromolecule. This material is then used in the preparation of emulsions, enabling the formation of a stable emulsion system without the addition of external emulsifiers and significantly improving the thermal stability of the encapsulated fragrances and flavors. To achieve the above-mentioned objectives and other advantages of the present invention, a method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifiers is provided, comprising: (I) A novel preparation method for an amphiphilically tunable cyclodextrin dendritic macromolecule: (1) Preparation method of cyclodextrin dendritic macromolecular intermediate The bridging macromolecule and catalyst were dissolved in deionized water and stirred until clear. Cyclodextrin was added and stirred continuously under heating conditions. The solution was dried at high temperature to obtain a yellow solid product. The yellow solid product was dissolved in deionized water and added dropwise to anhydrous ethanol. The precipitate was repeatedly washed with anhydrous ethanol and dried for later use. (2) Preparation method of amphiphilic tunable cyclodextrin dendritic macromolecules After preparing a saturated solution of the precipitate, a certain amount of polyol-ethanol solution was added, and the mixture was reacted in an oil bath for a period of time to obtain a liquid product. The liquid product was then added dropwise to anhydrous ethanol, and the precipitate was repeatedly washed with anhydrous ethanol and dried for later use.

[0005] In (1), the stirring temperature is 70℃-90℃ and the stirring time is 10-40 min; the drying temperature of the solution is 100℃-140℃ and the drying time is 3-6 h. In (2), the oil bath temperature is 100℃-140℃ and the oil bath time is 5-7 h.

[0006] Furthermore, by weight, the raw materials include the following components: 10-30 parts of bridging molecules, 1-10 parts of catalyst, 5-20 parts of cyclodextrin, 0.2-3 parts of polyol, 2-30 parts of ethanol, and 30-50 parts of deionized water.

[0007] Furthermore, the bridging macromolecule is preferably at least one of carboxylated cellulose, citric acid, maleic acid, and butanetetracarboxylic acid.

[0008] The catalyst is preferably at least one of sodium hypophosphite, sodium hypophosphite, sodium tripolyphosphate, and sodium pyrophosphate.

[0009] The cyclodextrin is preferably at least one of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin and hydroxypropyl-β-cyclodextrin.

[0010] The polyol is preferably at least one of ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecylol, dodecanol, tridecanol, tetradecanol, and pentadecanol.

[0011] (ii) A method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifier.

[0012] (1) A certain amount of polyol-modified cyclodextrin is dissolved in deionized water, and a certain amount of triacetylglycerol is added and stirred evenly in a water bath; the polyol-modified cyclodextrin is obtained by the above preparation method; (2) Add a certain amount of oil-soluble fragrance drop by drop, lower the water bath temperature and continue stirring.

[0013] (3) The above liquid is sheared at high speed using a high-speed shear emulsifier to obtain an emulsion product.

[0014] Further, in (1), the amount of polyol-modified cyclodextrin is 10-30 parts, the amount of deionized water is 100-300 parts, the amount of triacetin added is 2-6 parts by weight, the water bath temperature is 60℃-80℃, and the reaction time is 3-10 min. In (2), the amount of methyl anthranilate added is 1-3 parts by weight, the water bath temperature is 50℃-70℃, and the reaction time is 0.5-2.5 h. In (3), the heating temperature is such that the shear rate is 10000-18000 rpm, and the emulsification time is 5-25 min.

[0015] Furthermore, the oil-soluble fragrance is preferably at least one of menthol, isoamyl isovalerate, cinnamaldehyde, methyl anthranilate, and citral.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are: Polyol-modified cyclodextrins were prepared, overcoming the limitations of traditional cyclodextrins with fixed amphiphilicity. Polyols with different carbon chain lengths endowed the cyclodextrins with tunable amphiphilicity and emulsifying capabilities, allowing for targeted optimization of emulsion interfacial interactions. This allows them to serve as a core matrix for emulsion stability without relying on additional chemical emulsifiers. Using this polyol-modified cyclodextrin as an emulsion stabilizer, the resulting emulsion-free emulsion can be directly applied in the food flavoring field. It effectively addresses the flavor loss issues caused by the volatility and oxidation of flavorings during high-temperature processing, achieving long-lasting aroma retention and precise sustained release. Attached Figure Description

[0017] Figure 1 The infrared spectra of cyclodextrin, cyclodextrin intermediates, and polyol-modified cyclodextrin are shown in the embodiments of the preparation method of polyol-modified cyclodextrin-based emulsions according to the present invention. Figure 2 These are microstructure images of polyol-modified cyclodextrin-based emulsions without emulsifiers, as shown in the embodiments of the preparation method of the polyol-modified cyclodextrin-based emulsions according to the present invention. Figure 3 This is a particle size distribution diagram of the polyol-modified cyclodextrin-based emulsion without emulsifier in an embodiment of the preparation method of the polyol-modified cyclodextrin-based emulsion without emulsifier according to the present invention; Figure 4 Thermogravimetric analysis (TGA) diagram of the polyol-modified cyclodextrin-based emulsion without emulsifier in an example of the preparation method of the polyol-modified cyclodextrin-based emulsion without emulsifier according to the present invention; Figure 5 This is a stability graph of the polyol-modified cyclodextrin-based emulsion without emulsifier in an embodiment of the preparation method of the polyol-modified cyclodextrin-based emulsion without emulsifier according to the present invention. Detailed Embodiments The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0018] In this invention, during the preparation of cyclodextrin dendritic macromolecules, a first-step modification of cyclodextrin is performed using bridging macromolecules to form a cyclodextrin dendritic macromolecule intermediate. The bridging macromolecules are rich in carboxyl groups (-COOH), which can undergo esterification with the hydroxyl groups (-OH) of cyclodextrin, grafting cyclodextrin onto the bridging macromolecules. The residual carboxyl groups after grafting serve as active sites, providing ample reaction sites for the subsequent second-step modification reaction. After obtaining the intermediate with abundant active sites through bridging macromolecule modification of cyclodextrin, a polyol is further introduced. The carboxyl groups (-COOH) of the intermediate react with the hydroxyl groups (-OH) of the polyol in the second-step esterification reaction, achieving precise grafting of polyol carbon chain fragments onto the cyclodextrin, ultimately completing the modification of the cyclodextrin. By selecting polyols with different carbon chain lengths for grafting, the amphiphilicity of cyclodextrin dendritic macromolecules can be precisely controlled. The polyol-modified cyclodextrin dendritic macromolecules exhibit structural similarity to traditional chemical emulsifiers. This structural similarity endows cyclodextrin with excellent emulsifying capabilities, enabling directional alignment at the phase interface and effectively improving the stability of the emulsion system. Furthermore, the above two modification steps completely preserve the inherent hydrophobic cavity structure of cyclodextrin. The emulsifying ability of modified cyclodextrin and its inherent hydrophobic cavity work synergistically; the former ensures system stability, while the latter provides inclusion sites for guest molecules. Together, they lay the core molecular foundation for constructing a stable sustained-release system of flavor substances, addressing the performance shortcomings of traditional cyclodextrins in the construction of sustained-release systems from a mechanistic perspective.

[0019] A method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifiers includes: Example 1 15 g of citric acid and 5 g of sodium hypophosphite were dissolved in 40 g of deionized water and stirred until clear. Then, 12 g of γ-cyclodextrin was added, and the mixture was stirred continuously at 85 °C for 20 min. The solution was transferred to a 130 °C oven and dried for 4 h to obtain a yellow solid product. The yellow solid product was dissolved in deionized water and added dropwise to anhydrous ethanol. The precipitate was repeatedly washed with anhydrous ethanol and dried for later use. A saturated solution of the precipitate was prepared, and 33 g of octanol-ethanol solution was added. The mixture was reacted in an oil bath at 110 °C for 6.5 h to obtain a liquid product. The liquid product was added dropwise to anhydrous ethanol, and the precipitate was repeatedly washed with anhydrous ethanol and dried for later use.

[0020] Dissolve 1.5 g of polyol-modified cyclodextrin in 25 g of deionized water, add 0.3 g of triacetin, and stir in a water bath at 70 °C for 5 min. Add 0.2 g of methyl anthranilate dropwise, lower the water bath temperature to 60 °C, and continue stirring for 2 h. Use a high-speed shear emulsifier to shear at 15000 rpm for 10 min to obtain the emulsion product.

[0021] Example 2 10 g of maleic acid and 3 g of sodium hypophosphite were dissolved in 45 g of deionized water and stirred until clear. Then, 8 g of α-cyclodextrin was added, and the mixture was stirred continuously at 90 °C for 15 min. The solution was transferred to a 120 °C oven and dried for 5 h to obtain a yellow solid product. The yellow solid product was dissolved in deionized water and added dropwise to anhydrous ethanol. The precipitate was repeatedly washed with anhydrous ethanol and dried for later use. A saturated solution of the precipitate was prepared, and 40 g of nonanol-ethanol solution was added. The mixture was reacted in an oil bath at 135 °C for 5.5 h to obtain a liquid product. The liquid product was added dropwise to anhydrous ethanol, and the precipitate was repeatedly washed with anhydrous ethanol and dried for later use.

[0022] Dissolve 1 g of polyol-modified cyclodextrin in 30 g of deionized water, add 0.4 g of triacetin, and stir in a water bath at 65°C for 8 min. Add 0.25 g of citral dropwise, lower the water bath temperature to 55°C, and continue stirring for 1 h. Use a high-speed shear emulsifier to shear at 10000 rpm for 20 min to obtain the emulsion product.

[0023] Example 3 25 g of butanetetracarboxylic acid and 8 g of sodium tripolyphosphate were dissolved in 45 g of deionized water and stirred until clear. Then, 18 g of β-cyclodextrin was added, and the mixture was stirred continuously at 75 °C for 40 min. The solution was transferred to a 100 °C oven and dried for 6 h to obtain a yellow solid product. The yellow solid product was dissolved in deionized water and added dropwise to anhydrous ethanol. The precipitate was repeatedly washed with anhydrous ethanol and dried for later use. A saturated solution of the precipitate was prepared, and 30 g of dodecanol-ethanol solution was added. The mixture was reacted in an oil bath at 100 °C for 7 h to obtain a liquid product. The liquid product was added dropwise to anhydrous ethanol, and the precipitate was repeatedly washed with anhydrous ethanol and dried for later use.

[0024] Dissolve 2.5 g of polyol-modified cyclodextrin in 35 g of deionized water, add 0.5 g of triacetylglycerol, and stir in an 80°C water bath for 3 min. Add 0.3 g of cinnamaldehyde dropwise, lower the water bath temperature to 70°C, and continue stirring for 0.5 h. Use a high-speed shear emulsifier to shear at 18000 rpm for 15 min to obtain the emulsion product.

[0025] Example 4 30 g of carboxylated cellulose and 6 g of sodium pyrophosphate were dissolved in 50 g of deionized water and stirred until clear. Then, 15 g of hydroxypropyl-β-cyclodextrin was added, and the mixture was stirred continuously at 70 °C for 10 min. The solution was transferred to a 110 °C oven and dried for 3 h to obtain a yellow solid product. The yellow solid product was dissolved in deionized water and added dropwise to anhydrous ethanol. The precipitate was repeatedly washed with anhydrous ethanol and dried for later use. A saturated solution of the precipitate was prepared, and 20 g of tetradecyl alcohol-ethanol solution was added. The mixture was reacted in an oil bath at 140 °C for 5 h to obtain a liquid product. The liquid product was added dropwise to anhydrous ethanol, and the precipitate was repeatedly washed with anhydrous ethanol and dried for later use.

[0026] Dissolve 3 g of polyol-modified cyclodextrin in 40 g of deionized water, add 0.6 g of triacetin, and stir in a water bath at 60 °C for 10 min. Add 0.35 g of isoamyl isovalerate dropwise, lower the water bath temperature to 50 °C, and continue stirring for 2.5 h. Use a high-speed shear emulsifier to shear at 16000 rpm for 8 min to obtain the emulsion product.

[0027] Comparative Example 1 The difference between this comparative example and Example 1 is that the cyclodextrin was not modified and γ-cyclodextrin was used directly for emulsion preparation. The remaining preparation steps and process parameters were the same as in Example 1.

[0028] Comparative Example 2 The difference between this comparative example and Example 1 is that the cyclodextrin was not modified and γ-cyclodextrin was used directly for emulsion preparation. In addition, 0.5 g of Tween 80 was added as an emulsifier. The remaining preparation steps and process parameters were the same as those in Example 1.

[0029] Test methods Storage stability test: 7 g of emulsion was taken into a 10 ml glass bottle and sealed at 25°C for 7 days.

[0030] Centrifugation stability test: Use 15 ml centrifuge tubes, add 12 g of emulsion, and centrifuge at 3000 rpm for 15 min.

[0031] High temperature stability test: 7 g of emulsion was taken into a 10 ml glass bottle and sealed at 100°C for 6 hours.

[0032] Observe whether the sample shows phenomena such as layering, precipitation, or sedimentation. If these phenomena occur, it indicates that the emulsion has poor stability; otherwise, it indicates that the emulsion is relatively stable and can pass the stability test, and is recorded as stable. The results are shown in Table 1.

[0033] Table 1 shows the stability test results. Test Project 25℃，7 d 3000 rpm, 15 min 100℃，6 h Example 1 Stablize Stablize precipitation Example 2 Stablize Stablize Stablize Example 3 Stablize Stablize Stablize Example 4 Stablize Stablize Stablize Comparative Example 1 Layering Layering Layering Comparative Example 2 Layering Layering Layering

[0034] By grafting polyols with different carbon chain lengths onto cyclodextrin, the amphiphilicity of cyclodextrin can be precisely controlled. With increasing grafted carbon chain length, the lipophilicity of the polyol-modified cyclodextrin is enhanced, its emulsifying ability is improved, and it can better meet the interfacial stability requirements of oil-in-water emulsions, significantly improving the stability of the emulsion under different conditions.

[0035] In tests conducted at 25°C for 7 days and centrifuged at 3000 rpm for 15 minutes, Examples 1, 2, 3, and 4 remained stable without stratification, while Comparative Example 1 and Comparative Example 2 showed obvious stratification. This result indicates that a stable dispersion system can be formed under room temperature and centrifugation conditions through polyol modification.

[0036] In the high-temperature stability test, only Examples 2, 3, and 4 passed the stability test. This is because these examples grafted polyols with longer carbon chains, giving the system stronger lipophilicity. In contrast, Example 1, due to its shorter grafted carbon chain, and Comparative Examples 1 and 2, due to the lack of modification of the cyclodextrin, both resulted in excessively hydrophilic systems, making them more prone to phase separation at high temperatures and lacking the ability to withstand high temperatures.

[0037] In summary, this application first converts cyclodextrin into a dendritic macromolecular intermediate, and then grafts polyols via esterification to obtain polyol-modified cyclodextrin dendritic macromolecules. This material is then used in emulsion preparation, forming a stable emulsion system without the need for external emulsifiers and significantly improving the thermal stability of the encapsulated flavorings. This emulsion system can be widely applied in the food flavoring field, effectively mitigating flavor loss caused by volatilization and oxidation during high-temperature processing, achieving long-lasting aroma retention and controllable release, and providing a highly efficient and safe flavor encapsulation and delivery solution for related industries.

[0038] The number of devices and processing scale described herein are for simplification purposes. Applications, modifications, and variations of this invention will be readily apparent to those skilled in the art. Although embodiments of the invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for this invention, and further modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, this invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifiers, characterized in that, Includes the following steps: S1. Preparation of polyol-modified cyclodextrin dendritic macromolecules; S2. Dissolve the polyol-modified cyclodextrin dendritic macromolecules in deionized water, add a certain amount of triacetylglycerol and stir evenly in a water bath. S3. Add a certain amount of oil-soluble fragrance drop by drop, lower the water bath temperature and continue stirring; S4. Use a high-speed shear emulsifier to shear the liquid in the above steps at high speed to obtain the emulsion product; Specifically, step S1 includes the following steps: S11. Preparation of cyclodextrin dendritic macromolecular intermediates; S12. After preparing a saturated solution of the above-mentioned cyclodextrin dendritic macromolecular intermediate, a certain amount of polyol-ethanol solution is added, and the reaction is carried out in an oil bath to obtain a liquid product. S13. Add the liquid product dropwise into anhydrous ethanol. Wash the precipitate repeatedly with anhydrous ethanol and dry it for later use.

2. The method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifier as described in claim 1, characterized in that, Step S11 specifically includes the following steps: S111, the bridging macromolecule and catalyst are dissolved in deionized water, stirred until clear, then cyclodextrin is added, and the mixture is heated and stirred. S112. Dry the solution in step S111 to obtain a yellow solid product; S113. Dissolve the yellow solid product in deionized water and add it dropwise into anhydrous ethanol. Wash the precipitate repeatedly with anhydrous ethanol and dry it for later use.

3. The method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifier as described in claim 1, characterized in that, By weight, it includes the following components: 10-30 parts bridging molecule, 1-10 parts catalyst, 5-20 parts cyclodextrin, 0.2-3 parts polyol, 2-30 parts ethanol, and 30-50 parts deionized water.

4. The method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifier as described in claim 3, characterized in that, The bridging macromolecule is preferably at least one of carboxylated cellulose, citric acid, maleic acid, and butanetetracarboxylic acid.

5. The method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifier as described in claim 4, characterized in that, The catalyst is preferably at least one of sodium hypophosphite, sodium hypophosphite, sodium tripolyphosphate, and sodium pyrophosphate.

6. The method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifier as described in claim 5, characterized in that, The cyclodextrin is preferably at least one of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin and hydroxypropyl-β-cyclodextrin.

7. The method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifier as described in claim 6, characterized in that, The polyol is preferably at least one of ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecylol, dodecanol, tridecanol, tetradecanol, and pentadecanol.

8. The method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifier as described in claim 1, characterized in that, The amount of polyol-modified cyclodextrin dendritic macromolecules is 10-30 parts, the amount of deionized water is 100-300 parts, the amount of triacetin added is 2-6 parts by weight, the water bath temperature is 60℃-80℃, and the reaction time is 3-10 min.

9. The method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifier as described in claim 1, characterized in that, The amount of methyl anthranilate added is 1-3 parts by weight, the water bath temperature is 50℃-70℃, and the reaction time is 0.5-2.5h.

10. The method for preparing a polyol-modified cyclodextrin-based emulsion without emulsifier as described in claim 1, characterized in that, The heating temperature is such that the shear rate is 10,000-18,000 rpm and the emulsification time is 5-25 min.

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