High-encapsulation high-stability menthol emulsion and preparation method thereof

Abstract

The invention belongs to the field of food, and provides a preparation method of a high-encapsulation high-stability menthol emulsion, which comprises the following steps: dissolving menthol crystals in medium chain triglyceride to obtain a menthol oil phase; adding a food-grade nonionic emulsifier into the menthol oil phase, and uniformly mixing to obtain a mixed oil phase; dissolving the thickening agent powder in water to obtain a water phase; and under a stirring condition, injecting the mixed oil phase into the water phase to obtain the high-encapsulation and high-stability menthol emulsion. The menthol emulsion disclosed by the invention is prepared by stirring, the whole preparation process is consistent in condition, and high-energy consumption means such as high-pressure homogenization and heating are not needed, so that volatilization of menthol is effectively avoided, and the entrapment efficiency of menthol is improved. Meanwhile, the energy consumption cost of preparation is reduced. And the stability of the emulsion is improved by using the water-phase thickening agent. The menthol emulsion developed by the invention is prepared from food-grade raw materials, does not involve the use of organic auxiliaries, and has the characteristics of safety and health.

Description

Technical Field

[0001] The invention belongs to the field of food and relates to a high-encapsulation and high-stability menthol emulsion and a preparation method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Menthol, a volatile cyclic terpene alcohol extracted from mint plants, is the main component of mint essential oil and is often added to foods such as beverages and candies as a food flavor. However, menthol has poor water solubility, is extremely volatile, and has insufficient aroma persistence, which restricts its use effect. The emulsion encapsulation method is used to construct an oil-in-water carrier, and the physical barrier formed by the surfactant at the oil-water interface is used to achieve the encapsulation of menthol, which can effectively prevent the volatilization loss of menthol and is an effective technical means to improve the stability of menthol.

[0004] Patent CN202410482676.2 (a Pickering emulsion containing menthol and its preparation method) first uses cyclodextrin to include menthol to prepare a composite particle powder, further uses the composite particles as an emulsifier to stabilize soybean oil, and prepares a Pickering emulsion containing menthol by mixing and homogenizing. The emulsion shows good storage stability within 30 days and improves the bioavailability of menthol in the small intestine.

[0005] Patent CN201711177619.X (a method for preparing a peppermint essential oil nanoemulsion and its application in mouthwash) first synthesizes short-chain octenyl succinate glucan, and then uses a high shear dispersion homogenization method to prepare a peppermint essential oil nanoemulsion stabilized by short-chain octenyl succinate glucan and lecithin. It has a positive significance for the sustained release and stability of peppermint essential oil.

[0006] Patent CN202410450188.3 (a microemulsion for solubilizing essential oils / essential oil compounds and its preparation method) adopts a method of mixing a mixed oil phase containing plant essential oils and vegetable oils, and a mixed surfactant containing a nonionic surfactant and an alcohol co-surfactant in a certain proportion, and then adding a large volume of water to the mixed system under stirring conditions to prepare a microemulsion containing essential oils. Patent CN202310448840.3 (a peppermint essential oil nanoemulsion and its preparation method and application) also uses a similar method to prepare a nanoemulsion containing peppermint essential oil. These inventions are helpful to improve the water solubility and stability of essential oils.

[0007] Taking patents CN202410482676.2 and CN201711177619.X as examples, the current preparation of menthol emulsions requires appropriate heating to trigger emulsification, and homogenization techniques are often used to break the oil phase into fine droplets through high energy input, thereby promoting emulsification stability. However, the increase in feed temperature and the high shear effect of homogenization inevitably cause menthol to volatilize and lose during the emulsification process, reducing the encapsulation rate of the emulsion. At the same time, the heating and homogenization of feed in large-scale production methods increase energy consumption costs.

[0008] Taking patents CN202410450188.3 and CN202310448840.3 as examples, although a gentle stirring method is used to achieve the emulsification of peppermint essential oil and avoid the volatilization of menthol caused by high-energy means of heating the liquid, the former is mainly aimed at the fields of medicine, tobacco and daily chemicals, and the latter is aimed at the field of plant pesticide technology, especially the organic alcohols (such as ethanol, polyethylene glycol, n-propanol, isopropanol, propylene glycol, n-butanol and isobutanol, etc.) as auxiliary surfactants in the formula are easy to cause consumer disgust or have limited application scope in food applications. If no auxiliary emulsifier is used and only food-grade emulsifier is used, the stability of the prepared emulsion is poor. Summary of the invention

[0009] In order to solve the above problems, the present invention aims to develop a highly stable menthol emulsion suitable for the food field, and provides a highly encapsulated and highly stable menthol emulsion and a preparation method thereof. The system of the present invention is composed of an oil-soluble nonionic emulsifier and a carbohydrate colloid, has good encapsulation of oil-soluble menthol, and has high emulsion stability. At the same time, the present invention adopts a mild emulsification method to avoid the volatilization of menthol and improve the encapsulation rate of menthol.

[0010] In order to achieve the above object, the present invention adopts the following technical solution:

[0011] The first aspect of the present invention provides a method for preparing a highly encapsulated and highly stable menthol emulsion, comprising:

[0012] dissolving menthol crystals in medium chain triglycerides to obtain a menthol oil phase;

[0013] Adding a food-grade nonionic emulsifier to the menthol oil phase and mixing them evenly to obtain a mixed oil phase;

[0014] dissolving thickener powder in water to obtain an aqueous phase;

[0015] Under stirring conditions, the mixed oil phase is injected into the water phase to obtain a highly encapsulated and highly stable menthol emulsion.

[0016] In some embodiments, the mass ratio of the menthol crystals to the medium chain triglycerides is 1-5:5-15.

[0017] In some embodiments, the mass ratio of the menthol crystals to the food-grade nonionic emulsifier is 1-5:0.5-5.

[0018] In some embodiments, the food-grade nonionic emulsifier is selected from at least one of lecithin, mono- and di-glycerol fatty acid esters, citric acid fatty acid esters, Tween 80, and Span 80.

[0019] In some embodiments, the mass ratio of the thickener to water is 0.025-0.2:70-90, or 0.025-0.1:70-90.

[0020] In some embodiments, the thickener is selected from at least one of gellan gum, xanthan gum, carrageenan, pectin, sodium carboxymethyl cellulose, and sodium alginate.

[0021] In some embodiments, the emulsification speed is 650-800 rpm.

[0022] In some embodiments, the flow rate of the mixed oil phase injected into the water phase is 1-60 mL / min.

[0023] More specifically, they include:

[0024] (1) 1-5 parts of menthol crystals are dissolved in 5-15 parts of medium chain triglycerides by stirring to prepare an oil phase containing menthol.

[0025] (2) Add 0.5-5 parts of food-grade nonionic emulsifier to the menthol oil phase and stir evenly to prepare the mixed oil phase.

[0026] (The food-grade nonionic emulsifier includes but is not limited to one or more of lecithin, mono- and di-glycerol fatty acid esters, citric acid fatty acid esters, Tween 80, and Span 80)

[0027] (3) Dissolve 0.025-0.2 parts of thickener powder in 70-90 parts of purified water as the aqueous phase.

[0028] (The thickener includes but is not limited to one or more of gellan gum, xanthan gum, carrageenan, pectin, sodium carboxymethyl cellulose, and sodium alginate; preferably, the thickener is added in an amount of 0.025-0.1 parts)

[0029] (4) Under stirring at 650 rpm, the oil phase was slowly injected into the water phase using a syringe to obtain a highly encapsulated and highly stable menthol emulsion.

[0030] (The oil phase injection flow rate is 1-60mL / min. For large-scale production, multiple droppers can be used for injection)

[0031] The second aspect of the present invention provides a highly encapsulated and highly stable menthol emulsion prepared by the above method.

[0032] The third aspect of the present invention provides the use of the above-mentioned high-encapsulation and high-stability menthol emulsion in the food field.

[0033] Beneficial effects of the present invention

[0034] (1) The menthol emulsion of the present invention is prepared by stirring, and the conditions of the entire preparation process are consistent, and high-energy consumption means such as high-pressure homogenization and heating are not required, so the volatilization of menthol is effectively avoided, and the encapsulation rate of menthol is improved. At the same time, the energy consumption cost of the preparation is reduced. The use of the aqueous phase thickener improves the stability of the emulsion. The menthol emulsion developed by the present invention is prepared using food-grade raw materials, does not involve the use of organic additives, and has the characteristics of safety and health.

[0035] (2) The system of the present invention is composed of an oil-soluble nonionic emulsifier and a carbohydrate colloid, has good embedding properties for oil-soluble menthol, and has high emulsion stability. The preparation method of the present invention is simple, highly practical, and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the exemplary embodiments of the present invention and their description are used to explain the present invention, and do not constitute improper limitations on the present invention.

[0037] Figure 1 The appearance of menthol lotion;

[0038] Figure 2 Laser confocal microscopy images of Examples 1, 3 and Comparative Example 1;

[0039] Figure 3 Stability map. DETAILED DESCRIPTION

[0040] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0041] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0042] Embodiment 1:

[0043] (1) 1.0 g of menthol crystals were dissolved in 7.0 g of medium chain triglycerides by stirring to prepare an oil phase containing menthol.

[0044] (2) Add 3.0 g of mono- and di-glycerol fatty acid esters to the menthol oil phase and stir evenly to obtain the mixed oil phase.

[0045] (3) 0.1 g of pectin powder was dissolved in 88 g of purified water to form the aqueous phase.

[0046] (4) Under magnetic stirring at 650 rpm, the oil phase was slowly injected into the water phase using a syringe at an injection rate of 5 mL / min to obtain a menthol emulsion.

[0047] Embodiment 2:

[0048] The difference from Example 1 is that the mono- and di-glycerol fatty acid esters are replaced with citric acid fatty acid esters.

[0049] Embodiment 3:

[0050] The difference from Example 1 is that the amount of pectin added is 0.025 g.

[0051] Embodiment 4:

[0052] The difference from Example 1 is that the injection flow rate is increased to 10 mL / min.

[0053] Comparative Example 1:

[0054] The difference from Example 1 is that no water phase thickener is added.

[0055] Comparative Example 2:

[0056] The difference from Example 1 is that step (4) is changed to:

[0057] The oil and water phases were mixed, sheared for 2 minutes using a high shear dispersing emulsifier, and then high-pressure homogenized twice at a pressure of 500 bar using a nano homogenizer to obtain a menthol emulsion.

[0058] Experimental Example 1

[0059] The emulsions prepared in the examples and comparative examples were characterized by the following method:

[0060] 1. Use a camera to record the appearance of the emulsion;

[0061] 2. Use a micron particle size analyzer to analyze the particle size of the emulsion;

[0062] 3. Use Nile red to stain the emulsion, and use laser confocal microscopy to observe the microscopic morphology of the emulsion;

[0063] 4. Calculate the menthol encapsulation efficiency of the emulsion using gas chromatography;

[0064] 5. Use a stability analyzer to characterize the centrifugal stability of the emulsion and collect spectra and stability indices;

[0065] 6. The emulsion was stored at room temperature for 30 days. The menthol storage retention rate of the emulsion was obtained by calculating the ratio of the menthol encapsulation rate at the storage end point to the initial encapsulation rate.

[0066] Table 1 Performance data of emulsion

[0067]

[0068]

[0069] like Figure 1 As shown, the menthol emulsions prepared in Examples 1-4 are uniform white emulsions, indicating that the emulsions are successfully prepared. The sample in Comparative Example 1 shows obvious stratification, indicating that its stability is poor. The appearance of Comparative Example 2 is not significantly different from that of the examples.

[0070] like Figure 2 As shown, the oil droplets formed in Comparative Example 1 without adding an aqueous phase thickener are large and uneven. When 0.025 g of thickener is added to Example 3, the oil droplets are significantly reduced, with only a small amount of aggregation. When 0.1 g of aqueous phase thickener is added to Example 1, the oil droplet size and distribution are more uniform.

[0071] From the comparison between Examples 1 and 2, it can be seen that there are no significant differences in the emulsion particle size and stability index, menthol encapsulation efficiency and storage retention rate, indicating that the selected food nonionic emulsifiers meet the requirements of emulsion development.

[0072] From the comparison between Examples 1 and 3 and Comparative Example 1, it can be seen that as the concentration of the aqueous phase thickener decreases, the emulsion particle size and stability index slightly increase, and the encapsulation rate and retention rate are maintained at a relatively high level. In the comparative example without an aqueous phase thickener, the emulsion shows stratification, the stability index is significantly improved, and the menthol encapsulation rate and retention rate are significantly reduced, indicating that the addition of an aqueous phase thickener is the key to the present invention.

[0073] From the comparison between Examples 1 and 4, it can be seen that as the oil phase injection flow rate increases within the selected range, the emulsion particle size and stability index slightly increase, and the encapsulation efficiency and retention rate slightly decrease, but all are within an acceptable range, indicating that the selected injection flow rate range is the key point of the present invention.

[0074] like Figure 3 As shown, the stability curves of Examples 1-4 and Comparative Example 2 are concentrated, indicating that the transmittance of the emulsion does not change significantly during the centrifugation process. The end of the stability curve of Comparative Example 1 rises, indicating that the sample stability is poor, and the emulsion floats and layers during the centrifugation process, and the bottom gradually becomes clear.

[0075] From the comparison between Example 1 and Comparative Example 2, it can be seen that the latter adopts the conventional high-energy consumption method of high-shear dispersion and high-pressure homogenization, and the particle size of the prepared emulsion is significantly reduced, and the stability index is also maintained at a low level. However, the drastic processing conditions and high energy input cause the local temperature rise of the feed liquid to cause menthol to volatilize and lose during the processing process. The encapsulation rate of menthol is significantly lower than that of the low-energy consumption emulsification method of the embodiment, which shows the effectiveness of the method of the present invention in achieving high encapsulation and high stability of menthol emulsion.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a high-encapsulation and high-stability menthol emulsion, characterized in that: include: dissolving menthol crystals in medium chain triglycerides to obtain a menthol oil phase; Adding a food-grade nonionic emulsifier to the menthol oil phase and mixing them evenly to obtain a mixed oil phase; dissolving thickener powder in water to obtain an aqueous phase; Under stirring conditions, the mixed oil phase is injected into the water phase to obtain a highly encapsulated and highly stable menthol emulsion.

2. The method for preparing the high-encapsulation and high-stability menthol emulsion according to claim 1, characterized in that: The mass ratio of the menthol crystals to the medium chain triglycerides is 1-5:5-15.

3. The method for preparing the high-encapsulation and high-stability menthol emulsion according to claim 1, characterized in that: The mass ratio of the menthol crystals to the food-grade nonionic emulsifier is 1-5:0.5-5.

4. The method for preparing the high-encapsulation and high-stability menthol emulsion according to claim 1, characterized in that: The food-grade nonionic emulsifier is selected from at least one of lecithin, mono- and di-glycerol fatty acid esters, citric acid fatty acid esters, Tween 80 and Span 80.

5. The method for preparing the high-encapsulation and high-stability menthol emulsion according to claim 1, characterized in that: The mass ratio of the thickener to water is 0.025-0.2:70-90, or 0.025-0.1:70-90.

6. The method for preparing the high-encapsulation and high-stability menthol emulsion according to claim 1, characterized in that: The thickener is selected from at least one of gellan gum, xanthan gum, carrageenan, pectin, sodium carboxymethyl cellulose and sodium alginate.

7. The method for preparing the high-encapsulation and high-stability menthol emulsion according to claim 1, characterized in that: The emulsification rotation speed is 650-800 rpm.

8. The method for preparing the high-encapsulation and high-stability menthol emulsion according to claim 1, characterized in that: The flow rate of the mixed oil phase injected into the water phase is 1-60 mL / min.

9. The highly encapsulated and highly stable menthol emulsion prepared by the method according to any one of claims 1 to 8.

10. Use of the highly encapsulated and highly stable menthol emulsion according to claim 9 in the food field.

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