Nano-structure lipid carrier composite hydrogel capable of slowly releasing lemon fragrance and preparation method of nano-structure lipid carrier composite hydrogel

Abstract

The invention discloses a nano-structure lipid carrier composite hydrogel capable of slowly releasing lemon fragrance and a preparation method of the nano-structure lipid carrier composite hydrogel. The method comprises the following steps: preparing a nano-structure lipid carrier containing lemon fragrance by adopting a hot melting ultrasonic method, adding the nano-structure lipid carrier into carboxymethyl chitosan / sodium alginate hydrogel, and incubating in a water bath at 37 DEG C to obtain the composite hydrogel. The lemon aroma component nanostructure lipid carrier composite hydrogel is prepared into different forms to be applied to the acid beverage. The nano-structure lipid carrier composite hydrogel provided by the invention has good acid stability and realizes good controlled release of lemon aroma substances.

Description

Technical Field

[0001] The present invention relates to the technical field of nanoparticle carrier preparation, and particularly to a nanostructured lipid carrier composite hydrogel with slow release of lemon aroma and a preparation method thereof, which can be applied to acidic beverages to maintain lemon aroma components. Background Art

[0002] In recent years, with the continuous increase in the demand for the beverage market, acidic beverages have gradually become an indispensable part of our daily lives. As a natural aroma component, limonene has a strong citrus fragrance, which can add a fresh and natural taste to acidic beverages, enhancing the aroma and refreshing taste of the beverages. The acidic beverages themselves have a sour taste, and the combination of lemon aroma components and sourness makes the taste of the beverages more layered, being both fresh and not monotonous. It can avoid overly prominent sourness and improve the overall taste balance of the beverages. Therefore, the application prospect of limonene in acidic beverages is very broad and has great potential.

[0003] However, due to the pH value of acidic beverages usually being lower than 4.0< / , in a low pH environment, lemon aroma components are extremely prone to decomposition, resulting in the weakening of their aroma and possibly generating strange smells. The nanostructured lipid carrier composite hydrogel system, as an emerging drug controlled release technology, has unique advantages in its good biocompatibility, biodegradability, and precise drug release regulation ability. With the continuous development of materials science, nanotechnology, and the biomedical field, the nanostructured lipid carrier composite hydrogel will undoubtedly play a more important role in future drug delivery systems. Summary of the Invention

[0004] The purpose of the present invention is to provide a nanostructured lipid carrier composite hydrogel with slow release of aroma and a preparation method thereof. This method is not only simple to operate, can slowly release aroma, but also reduces the release rate of lemon aroma components during storage, broadening the application range of lemon aroma components.

[0005] The specific technical solutions are as follows:

[0006] A preparation method of a nanostructured lipid carrier composite hydrogel with slow release of lemon aroma, comprising:

[0007] (1) Weigh a certain mass of solid lipid, liquid lipid, and lemon aroma components and mix them as the lipid phase; use an aqueous solution of Span 65 as the aqueous phase. The lipid and the aqueous phase are heated separately, preferably at

[0008] 75 °C< /

[0008] ;

[0008] (2) Add the lipid phase to the aqueous phase, perform high-speed shearing and ultrasonic treatment, and finally cool to obtain a nanostructured lipid carrier of lemon aroma components;

[0009] (3) Dissolve carboxymethyl chitosan powder in acetic acid, and neutralize it with NaOH solution to obtain the first solution. Dissolve sodium alginate in NaCl solution to prepare the second solution. After mixing the two, add nanostructured lipid carriers of lemon aroma components. Mix sodium sulfate and calcium chloride to prepare a chelating solution. After mixing the mixed solution with the chelating solution and incubating in a water bath, a nanostructured lipid carrier composite hydrogel solution of lemon aroma components is obtained.

[0010] (4) Prepare the obtained composite hydrogel solution into microbeads or lyophilized powder; specifically as follows: Add a certain amount of calcium chloride to the composite hydrogel solution, and drop it out one by one with a dropper to prepare hydrogel microbeads; Freeze-dry the composite hydrogel solution in a freeze dryer for 72 hours to prepare a composite hydrogel lyophilized powder.

[0011] In the above technical solution, further, in the step (1), the solid lipids include but are not limited to glyceryl tristearate (GTS), glyceryl monostearate (GMS), glyceryl distearate (GDS), monopalmitin (SPEG), and monolaurin (GML), and the lemon aroma components include but are not limited to limonene and citral;

[0012] Preferably, the mass ratio of solid lipid: liquid lipid: lemon aroma component is 1:1:1 to 2, and more preferably 1:1:1.

[0013] Preferably, in the step (1), glyceryl tristearate (GTS) is selected as the solid lipid, and medium-chain triglyceride is selected as the liquid lipid.

[0014] It has been found through experiments that the combination of glyceryl tristearate (GTS) and medium-chain triglyceride, compared with the glyceryl monostearate / medium-chain triglyceride system used in traditional nanostructured lipid carriers, the symmetric triester structure of GTS combines with the short-chain characteristics of MCT. When prepared by the hot melt ultrasonic method, the particle size of NLCs prepared with GTS is less than 230 nm, with good uniformity, a stable Zeta potential, and a high encapsulation efficiency (>80%).

[0015] Preferably, in the step (1), the mass concentration of span 65 in the aqueous phase is 0.5% to 3%, and more preferably 1.5 to 2.5%.

[0016] Preferably, in the step (2), the rotation speed of high-speed shearing is 8000 to 12000 rpm, and the time is 8 to 12 minutes, more preferably 9000 to 11000 rpm, and the time is 10 to 12 minutes.

[0017] Preferably, in the step (2), the power of ultrasonic treatment is 200 to 300 W, and the treatment time is 10 to 30 minutes, more preferably 250 to 280 W, and the treatment time is 20 minutes.

[0018] Further, in the step (2), the rotation speed of high-speed shearing is 10,000 rpm and the time is 10 min. The power of ultrasonic treatment is 260 W and the treatment time is 20 min. It is found through experiments that at this time, the particle size of the prepared nanostructured lipid carriers is the smallest and the release rate of lemon aroma components is the lowest.

[0019] Preferably, in the step (3), the carboxyl substitution degree of carboxymethyl chitosan is 5% - 25%, more preferably 10% - 22%.

[0020] More preferably, in the step (3), when the carboxyl substitution degree of carboxymethyl chitosan is 17.68 ± 0.14%, it is found through experiments that the release rate of the entrapped lemon aroma components at high temperature is the lowest and the stability is more excellent under acidic and high-temperature conditions.

[0021] Preferably, in the step (3), the carboxymethyl chitosan powder is dissolved in acetic acid and neutralized with 0.1 mol / L sodium hydroxide to form a first solution with a final concentration of 0.4% - 0.8% (wt / vol), more preferably 0.6% (wt / vol).

[0022] Preferably, in the step (3), sodium alginate is dissolved in 0.15 mol / L sodium chloride to form a second solution with a final concentration of 1.2% - 1.5% (wt / vol), more preferably 1.4% (wt / vol).

[0023] Preferably, in the step (3), the first solution and the second solution are mixed in a volume ratio of 1:1 - 2.

[0024] Preferably, in the step (3), 30 mM sodium sulfate and 70 mM calcium chloride are mixed in a volume ratio of 1 - 2:1 to form a chelating solution.

[0025] Preferably, in the step (4), the amount of calcium chloride is 1% - 2% (wt / vol), preferably 1.2% - 1.5% (wt / vol).

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The preparation process of the present invention is simple and suitable for industrial production.

[0028] (2) By forming a nanostructured lipid carrier composite hydrogel of lemon aroma components, the release rate of lemon aroma components during storage can be greatly reduced, which is beneficial to the development of acidic beverages containing nanostructured lipid carrier composite hydrogel of lemon aroma components. The present invention improves the stability of aroma components such as limonene in beverages, so as to provide more ideas for the industrial application of lemon aroma components in practice.

[0029] (3) Provide a nanostructured lipid carrier composite hydrogel with slow aroma release, opening up new ideas for the industrial applications of substances containing lemon aroma, such as limonene and citral. Description of the Drawings

[0030] Figure 1 is the release rate of limonene in the acidic beverage system;

[0031] Figure 2 is the release rate of limonene during the pasteurization process of the composite hydrogel in the acidic system;

[0032] Figure 3 is the FTIR analysis of Examples 3, 4, 7, and 8. Detailed Embodiments

[0033] The present invention will be further explained below in conjunction with specific embodiments. The present invention is implemented according to the technical solution of the invention, and detailed implementation methods and operation steps are given, but the protection scope of the present invention is not limited to the following embodiments. The experimental methods without specific conditions noted in the following embodiments are usually carried out under conventional conditions.

[0034] The method for measuring the release rate of limonene in the acidic beverage simulation system is as follows: Store the sample in an environment of 25 °C and measure its indicators every 15 days. Calculate the RR% of limonene in the acidic beverage simulation system by measuring the contents of free limonene and total limonene. The free limonene is separated from the beverage by centrifugal ultrafiltration. Specifically, extract 2 mL of the acidic beverage simulation system loaded with limonene, and then use a high-speed refrigerated centrifuge to centrifuge at 8000 rpm for 20 min at 4 °C. Collect the filtrate, dilute it with absolute ethanol, and measure it with a UV-visible spectrometer (measured at a wavelength of 209 nm. To evaluate the total amount of limonene, dissolve the solution in absolute ethanol and sonicate it for 30 minutes to dissolve. Subsequently, dilute the solution with absolute ethanol and measure the absorbance value.

[0035] The thermal stability of the NLCs composite hydrogel under acidic conditions is evaluated by pasteurization (65 °C, 30 minutes). During these treatments, the system is maintained in a solution with a pH value of 4.5. During the pasteurization process, samples are collected at different time points of 0, 10, 20, and 30 minutes, and then the release rate RR(%) is measured.

[0036] RR(%) is calculated according to the following formula:

[0037]

[0038] Example 1

[0039] A method for preparing a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma, the specific steps are as follows:

[0040] (1) Prepare nanostructured lipid carriers loaded with limonene by the hot-melt ultrasonic method. Weigh 0.25 g of glyceryl tristearate (GTS), 0.25 g of medium-chain triglyceride (MCT) and 0.25 g of limonene, and mix to form a lipid phase. The aqueous phase consists of distilled water and 1.0 g of Span 65. The lipid and aqueous phases are heated to 75 °C respectively.

[0041] (2) Add the lipid phase to the aqueous phase, and disperse it at high speed for 10 min at 10000 rpm using a high-speed shear machine. Treat it with an ultrasonic cell disruptor (40% & 260 W, ultrasonic on for 3.0 s and off for 3.0 s) for 20 min. Store the obtained limonene nanostructured lipid dispersion in a refrigerator at 4 °C to form a stable NLCs dispersion (GTS-NLCs).

[0042] (3) Dissolve carboxymethyl chitosan powder with a degree of substitution of 17.68 ± 0.14% in acetic acid, and add 0.1 mol / L sodium hydroxide for neutralization to form a solution with a final concentration of 0.6% (wt / vol), that is, chitosan solution. Dissolve sodium alginate in 0.15 mol / L sodium chloride to form a solution with a final concentration of 1.4% (wt / vol), that is, sodium alginate solution. Finally, mix the chitosan solution and sodium alginate solution in a ratio of 1:1, and add GTS-NLCs to obtain a hydrogel. Mix 30 mM sodium sulfate and 70 mM calcium chloride in a volume ratio of 2:1 to form a chelating solution. Incubate the prepared chelating solution and hydrogel in a water bath at 37 °C, and then collect the composite hydrogel (NLC-CAH1). Add calcium chloride to it to make hydrogel microspheres.

[0043] (4) Configure an acidic beverage simulation system according to the following formula: 10% glucose, 20 mM citric acid and sodium citrate buffer solution, 0.1% sodium benzoate, dissolved in ultrapure water, and finally adjust the pH value of the obtained beverage system to about 3.50 with 1 M citric acid. According to the standard that the effective addition amount of limonene is 10 mg / kg, add limonene nanostructured lipid carrier composite hydrogel microspheres to the acidic beverage simulation system. The sample is heated in a water bath at 65 °C for 30 minutes for pasteurization treatment. After sterilization and cooling, store the sample in an environment at 25 °C, and measure its various indicators every 5 days.

[0044] Under the storage condition of 25 °C for NLC-CAH1 microsphere beverage, the release results of limonene in the acidic beverage are as Figure 1 shown: The 45-day cumulative release rate of limonene is 28.17 ± 0.19%.

[0045] Example 2

[0046] A preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma is as follows:

[0047] (1) Prepare nanostructured lipid carriers loaded with limonene by the hot-melt ultrasonic method. Weigh 0.25 g of glyceryl tristearate (GTS), 0.25 g of medium-chain triglyceride (MCT), and 0.25 g of limonene, and mix them to form a lipid phase. The aqueous phase consists of distilled water and 1.0 g of Span 65. The lipid and aqueous phases are heated to 75 °C respectively.

[0048] (2) Add the lipid phase to the aqueous phase, and disperse it at a high speed of 10000 rpm for 10 min using a high-speed shear machine. Treat it for 20 min using an ultrasonic cell disruptor (40% & 260 W, ultrasound on for 3.0 s and off for 3.0 s). Store the obtained limonene nanostructured lipid NLCs dispersion in a refrigerator at 4 °C to form a stable NLCs dispersion (GTS-NLCs).

[0049] (3) Dissolve carboxymethyl chitosan powder with a degree of substitution of 17.68 ± 0.14% in acetic acid, and add 0.1 mol / L sodium hydroxide for neutralization to form a solution with a final concentration of 0.6% (wt / vol), namely the chitosan solution. Dissolve sodium alginate in 0.15 mol / L sodium chloride to form a solution with a final concentration of 1.4% (wt / vol), namely the sodium alginate solution. Finally, mix the chitosan solution and the sodium alginate solution in a ratio of 1:1, and add GTS-NLCs to obtain a hydrogel. Prepare a chelating solution of 30 mM sodium sulfate and 70 mM calcium chloride with a volume ratio of 2:1. Incubate the prepared chelating solution and the hydrogel in a water bath at 37 °C, and then collect the composite hydrogel (NLC-CAH1). Freeze-dry it to make a freeze-dried powder.

[0050] (4) Configure an acidic beverage simulation system according to the following formula: 10% glucose, 20 mM citric acid and sodium citrate buffer solution, 0.1% sodium benzoate, dissolve in ultrapure water, and finally adjust the pH value of the obtained beverage system to about 3.50 with 1 M citric acid. According to the standard that the effective addition amount of limonene is 10 mg / kg, add the freeze-dried powder of the limonene nanostructured lipid carrier composite hydrogel to the acidic beverage simulation system. Heat the sample in a water bath at 65 °C for 30 minutes for pasteurization treatment. After sterilization and cooling, store the sample in an environment at 25 °C, and measure its various indicators every 5 days.

[0051] Under the storage condition of 25 °C for the NLC-CAH1 powder beverage, the release results of limonene in the acidic beverage are as Figure 1 shown: The cumulative release rate of limonene in 45 days is 27.75 ± 0.88%.

[0052] Example 3

[0053] A preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma is as follows:

[0054] (1) Prepare nanostructured lipid carriers loaded with limonene by the hot-melt ultrasonic method. Weigh 0.25 g of glyceryl tristearate (GTS), 0.25 g of medium-chain triglyceride (MCT) and 0.25 g of limonene, and mix them to form a lipid phase. The aqueous phase consists of distilled water and 1.0 g of Span 65. The lipid and the aqueous phase are heated to 75 °C respectively.

[0055] (2) Add the lipid phase to the aqueous phase, and disperse it at a high speed of 10000 rpm for 10 min using a high-speed shear machine. Treat it with an ultrasonic cell disruptor (40% 260 W, ultrasound on for 3.0 s and off for 3.0 s) for 20 min. Store the obtained NLCs dispersion in a refrigerator at 4 °C to form a stable NLCs dispersion.

[0056] (3) Dissolve carboxymethyl chitosan powder with a degree of substitution of 17.68 ± 0.14% in acetic acid, and add 0.1 mol / L sodium hydroxide for neutralization to form a solution with a final concentration of 0.6% (wt / vol). Dissolve sodium alginate in 0.15 mol / L sodium chloride to form a solution with a final concentration of 1.4% (wt / vol). Finally, mix the chitosan solution and the sodium alginate solution in a ratio of 1:1, and add GTS-NLCs. Prepare a chelating solution with 30 mM sodium sulfate and 70 mM calcium chloride to a volume ratio of 2:1. Incubate the prepared chelating solution and the hydrogel in a 37 °C water bath, and then collect the composite hydrogel (NLC-CAH1).

[0057] The release results of limonene are as Figure 2 shown: NLC-CAH1 releases 3.31%, 5.38%, and 7.41% respectively during pasteurization at 10, 20, and 30 min.

[0058] Example 4

[0059] A preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma is as follows:

[0060] (1) Prepare nanostructured lipid carriers loaded with limonene by the hot-melt ultrasonic method. Weigh 0.25 g of glyceryl tristearate (GTS), 0.25 g of medium-chain triglyceride (MCT) and 0.25 g of limonene, and mix them to form a lipid phase. The aqueous phase consists of distilled water and 1.0 g of Span 65. The lipid and the aqueous phase are heated to 75 °C respectively.

[0061] (2) Add the lipid phase to the aqueous phase and disperse it at high speed for 10 min at 10,000 rpm using a high-speed shear machine. Treat it for 20 min using an ultrasonic cell disruptor (40% 260 W, ultrasound on for 3.0 s and off for 3.0 s). Store the obtained NLCs dispersion in a refrigerator at 4 °C to form a stable NLCs dispersion.

[0062] (3) Dissolve carboxymethyl chitosan powder with a degree of substitution of 21.36 ± 0.28% in acetic acid, and add 0.1 mol / L sodium hydroxide for neutralization to form a solution with a final concentration of 0.6% (wt / vol). Dissolve sodium alginate in 0.15 mol / L sodium chloride to form a solution with a final concentration of 1.4% (wt / vol). Finally, mix the chitosan solution and the sodium alginate solution in a ratio of 1:1, and add GTS-NLCs. Prepare a chelating solution of 30 mM sodium sulfate and 70 mM calcium chloride with a volume ratio of 2:1. Incubate the prepared chelating solution and the hydrogel in a water bath at 37 °C, and then collect the composite hydrogel (NLC-CAH2).

[0063] The release results of limonene are as Figure 2 shown: NLC-CAH2 releases 3.99%, 6.47%, and 8.18% respectively during pasteurization at 10, 20, and 30 min.

[0064] Example 5

[0065] An acidic beverage containing limonene nanostructured lipid carriers and a preparation method thereof, the specific steps are as follows:

[0066] (1) Prepare limonene-loaded nanostructured lipid carriers by the hot melt ultrasound method. Weigh 0.25 g of glyceryl tristearate (GTS), 0.25 g of medium-chain triglyceride (MCT), and 0.25 g of limonene, and mix to form a lipid phase. The aqueous phase consists of distilled water and 1.0 g of Span 65. Heat the lipid and aqueous phases to 75 °C respectively.

[0067] (2) Add the lipid phase to the aqueous phase and disperse it at high speed for 10 min at 10,000 rpm using a high-speed shear machine. Treat it for 20 min using an ultrasonic cell disruptor (40% 260 W, ultrasound on for 3.0 s and off for 3.0 s). Store the obtained NLCs dispersion in a refrigerator at 4 °C to form a stable NLCs dispersion.

[0068] (3) Prepare an acidic beverage simulation system according to the following formula: 10% glucose, 20 mM citric acid and sodium citrate buffer solution, 0.1% sodium benzoate, dissolved in ultrapure water, and finally adjust the pH value of the obtained beverage system to about 3.50 with 1 M citric acid. Add limonene nanostructured lipid carriers to the acidic beverage simulation system according to the standard of an effective limonene addition amount of 10 mg / kg. Heat the sample in a water bath at 65 °C for 30 minutes for pasteurization. After sterilization, cool the sample and store it in an environment at 25 °C, and measure its various indicators every 5 days.

[0069] Under the storage condition of 25 °C for the acidic beverage with limonene nanostructured lipid carriers, the release results of limonene are as Figure 1 shown: The 45-day cumulative release rate of limonene is 50.82 ± 2.17%.

[0070] Example 6

[0071] An acidic beverage containing limonene hydrogel and its preparation method are as follows:

[0072] (1) Dissolve carboxymethyl chitosan powder with a degree of substitution of 17.68 ± 0.14% in acetic acid, add 0.1 mol / L sodium hydroxide for neutralization to form a solution with a final concentration of 0.6% (wt / vol). Dissolve sodium alginate in 0.15 mol / L sodium chloride to form a solution with a final concentration of 1.4% (wt / vol). Finally, mix the chitosan solution and the sodium alginate solution in a ratio of 1:1, and add limonene to obtain a hydrogel. Prepare a chelating solution of 30 mM sodium sulfate and 70 mM calcium chloride with a volume ratio of 2:1. Incubate the prepared chelating solution and the hydrogel in a water bath at 37 °C, and then collect the limonene hydrogel (CAH1).

[0073] (2) Prepare an acidic beverage simulation system according to the following formula: 10% glucose, 20 mM citric acid and sodium citrate buffer solution, 0.1% sodium benzoate, dissolved in ultrapure water, and finally adjust the pH value of the obtained beverage system to about 3.50 with 1 M citric acid. Add limonene hydrogel to the acidic beverage simulation system according to the standard of an effective limonene addition amount of 10 mg / kg. Heat the sample in a water bath at 65 °C for 30 minutes for pasteurization. After sterilization, cool the sample and store it in an environment at 25 °C, and measure its various indicators every 5 days.

[0074] Under the storage condition of 25 °C for the acidic beverage with limonene hydrogel, the release results of limonene are as Figure 1 shown: The 45-day cumulative release rate of limonene is 49.90 ± 2.12%.

[0075] Example 7

[0076] A limonene-containing nanostructured lipid carrier and its preparation method are as follows:

[0077] (1) Prepare the nanostructured lipid carrier loaded with limonene by the hot melt ultrasonic method. Weigh 0.25 g of glyceryl tristearate (GTS), 0.25 g of medium-chain triglyceride (MCT), and 0.25 g of limonene, and mix them to form the lipid phase. The aqueous phase consists of distilled water and 1.0 g of Span 65. Heat the lipid phase and the aqueous phase to 75 °C respectively.

[0078] (2) Add the lipid phase to the aqueous phase, and disperse it at a high speed of 10000 rpm for 10 min using a high-speed shear machine. Treat it with an ultrasonic cell disruptor (40% 260 W, ultrasound on for 3.0 s and off for 3.0 s) for 20 min. Store the obtained NLCs dispersion in a refrigerator at 4 °C to form a stable NLCs dispersion.

[0079] (3) Determine RR% after pasteurizing the sample (65 °C, 30 min), and collect samples during pasteurization (10, 20, 30 min).

[0080] The release results of limonene are as Figure 2 shown: GTS-NLCs release 2.87%, 7.57%, and 10.45% respectively during pasteurization at 10, 20, and 30 min.

[0081] Example 8

[0082] A limonene-containing nanostructured lipid carrier and its preparation method are as follows:

[0083] (1) Prepare the nanostructured lipid carrier loaded with limonene by the hot melt ultrasonic method. Weigh 0.25 g of glyceryl monostearate (GMS), 0.25 g of medium-chain triglyceride (MCT), and 0.25 g of limonene, and mix them to form the lipid phase. The aqueous phase consists of distilled water and 1.0 g of Span 65. Heat the lipid and aqueous phases to 75 °C respectively.

[0084] (2) Add the lipid phase to the aqueous phase, and disperse it at a high speed of 10000 rpm for 10 min using a high-speed shear machine. Treat it with an ultrasonic cell disruptor (40% 260 W, ultrasound on for 3.0 s and off for 3.0 s) for 20 min. Store the obtained NLCs dispersion in a refrigerator at 4 °C to form a stable NLCs dispersion.

[0085] (3) Determine RR% after pasteurizing the sample (65 °C, 30 min), and collect samples during pasteurization (10, 20, 30 min).

[0086] The release results of limonene are as Figure 2As shown: GMS-NLCs released 4.08%, 8.59%, and 13.72% respectively during pasteurization at 10, 20, and 30 minutes.

[0087] Comparative Example 1

[0088] An acidic beverage containing limonene and its preparation method are as follows:

[0089] (1) Configure an acidic beverage simulation system according to the following formula: 10% glucose, 20 mM citric acid and sodium citrate buffer solution, 0.1% sodium benzoate, dissolved in ultrapure water, and finally adjust the pH value of the obtained beverage system to about 3.50 with 1 M citric acid. Add limonene to the acidic beverage simulation system according to the standard of an effective addition amount of 10 mg / kg of limonene. The sample is heated in a water bath at 65 °C for 30 minutes for pasteurization treatment. After sterilization, it is cooled, and the sample is stored in an environment at 25 °C, and its various indicators are measured every 5 days.

[0090] Under the storage condition of 25 °C for the limonene beverage, the release results of limonene in the acidic beverage are as Figure 1 shown: The 45-day cumulative release rate of limonene is 78.39 ± 1.97%.

[0091] FTIR was used to analyze the interaction between limonene, nanostructured lipid carriers, and hydrogels. The FTIR peak spectra are respectively as Figure 3 shown. The characteristic absorption peaks of limonene at 2965, 2917, and 2856 cm -1 show the C-H stretching of CH and the methylene group. Some characteristic peaks of limonene also appeared at 1645 cm -1 (-CH=CH). In the FTIR spectra of Examples 3, 4, 7, and 8), the intensities of some peaks corresponding to limonene (such as 2965 cm -1 , 1376 cm -1 , 1123 cm -1 ) weakened or disappeared, indicating that limonene had been successfully encapsulated in NLCs. In addition to limonene, a broad band appeared at 3000 cm -1 -3600 cm -1 , representing the characteristic absorption peak of the stretching vibration of hydroxyl groups in solid lipids.

[0092] It can be seen from the comparison of the above examples that under the storage condition of 25 °C, after pasteurization, the NLC composite hydrogel provides a dual protection mechanism, and the release rate of limonene is greatly reduced.

Claims

1. A preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma, characterized in that, It includes the following steps: (1) Weigh solid fat, medium-chain triglyceride (MCT) and lemon aroma components and mix them as the lipid phase; use an aqueous solution of Span 65 as the aqueous phase; heat the lipid phase and the aqueous phase separately; (2) Add the lipid phase to the aqueous phase, perform high-speed shearing and ultrasonic treatment, and finally cool to obtain a lemon aroma component nanostructured lipid carrier; (3) Dissolve carboxymethyl chitosan powder in acetic acid, neutralize it with NaOH solution to form a first solution, dissolve sodium alginate in an NaCl solution to prepare a second solution, mix the two and add the lemon aroma component nanostructured lipid carrier to obtain a mixed solution; mix sodium sulfate and calcium chloride to prepare a chelating solution; Mix the mixed solution with the chelating solution and incubate in a water bath to obtain a lemon aroma component nanostructured lipid carrier composite hydrogel solution; (4) Prepare the obtained composite hydrogel solution into microbeads or lyophilized powder, which can slowly release lemon aroma.

2. The preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma as described in claim 1, characterized in that, In the step (1), the solid fat is selected from glyceryl monostearate (GMS), glyceryl distearate (GDS), glyceryl tristearate (GTS), stearic acid monoglyceride (SPEG) and lauric acid monoglyceride (GML), preferably glyceryl tristearate (GTS).

3. The preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma as described in claim 1, characterized in that, In the step (1), the mass ratio of the solid fat, medium-chain triglyceride (MCT) and lemon aroma components is 1:1:1 to 2.

4. The preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma as described in claim 1, characterized in that, In the step (1), the mass concentration of Span 65 in the aqueous phase is 0.5% to 3%.

5. The preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma as described in claim 1, characterized in that, In the step (2), the rotation speed of the high-speed shearing is 8000 to 12000 rpm, the time is 8 to 12 min, the power of the ultrasonic treatment is 200 to 300 W, and the treatment time is 10 to 30 min.

6. The preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma as described in claim 1, characterized in that, In the step (3), the carboxyl substitution degree of the carboxymethyl chitosan is 5% to 25%.

7. The preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma as described in claim 1, characterized in that, In the step (3), dissolve the carboxymethyl chitosan powder in acetic acid, add 0.1 mol / L sodium hydroxide for neutralization to form a first solution with a final concentration of carboxymethyl chitosan of 0.4% to 0.8% (wt / vol); dissolve sodium alginate in 0.15 mol / L sodium chloride to form a second solution with a final concentration of sodium alginate of 1.2% to 1.5% (wt / vol).

8. The preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma as described in claim 7, characterized in that, In the step (3), the first solution and the second solution are mixed in a volume ratio of 1:1 to 2.

9. The preparation method of a nanostructured lipid carrier composite hydrogel with slow-release lemon aroma as described in claim 1, characterized in that, In the step (3), mix 30 mM sodium sulfate and 70 mM calcium chloride in a volume ratio of 1 to 2:1 to form a chelating solution.

10. A nanostructured lipid carrier composite hydrogel with slow-release lemon aroma prepared by the method according to any one of claims 1-9.

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