Flavor high internal phase emulsion having inner and outer chambers and method of making same

Abstract

The present application relates to high internal phase emulsion preparation technical field, especially to a kind of flavour high internal phase emulsion with inner and outer chamber and preparation method thereof.Preparation method includes constructing hierarchical type I flavour microemulsion: corn alcohol-soluble protein is dissolved in ethanol, and Zein-limonene microemulsion mother liquor is prepared by emulsification and anti-solvent method;Constructing hierarchical type II outer chamber condensation microemulsion: preparing microcrystalline chitin mother liquor, Zein-limonene microemulsion mother liquor is mixed with microcrystalline chitin mother liquor, and Zein-limonene-CNCs complex condensation microemulsion is formed using LBL technology;Constructing hierarchical type III inner and outer chamber flavour high internal phase emulsion: taking Zein-limonene-CNCs complex condensation microemulsion, flavour mixed oil is added, and high-speed shearing homogenization is obtained to obtain flavour high internal phase emulsion with inner and outer chamber.The inner and outer chamber flavour high internal phase emulsion obtained by the present application has good lipid oxidation stability, which helps to prolong product shelf life;It has pH responsiveness and flavour controlled-release effect, and can significantly reduce the loss of flavour.

Description

Technical Field

[0001] This invention relates to the field of high internal phase emulsion preparation technology, and in particular to a flavorful high internal phase emulsion with inner and outer chambers and its preparation method. Background Technology

[0002] With socio-economic development and the improvement of people's living standards, people's requirements for food have gradually shifted from "eating enough" to "eating well." The "New Era Chinese Flavor Trend Map" published by KAIRE in 2023 mentioned that today's consumers have their own considerations when choosing food products, paying more attention to scientific formulations, cost-effectiveness, and emotional value. Among these, taste and flavor, and healthy ingredients have the greatest impact on purchasing decisions, and enriching flavor profiles can bring consumers a better experience. To meet the demands of satisfying appetites, there is an urgent need to develop new encapsulation and delivery systems for carrying diverse flavor substances to break through existing technological bottlenecks.

[0003] Food emulsions are complex soft matter systems, and emulsion products are widely found in our daily foods, such as margarine, sauces, plant-based protein drinks, and mayonnaise. However, compared to single-chamber emulsions such as oil-in-water (O / W) or water-in-oil (W / O) emulsions, multi-chamber emulsions, such as multi-chambered water-in-oil-in-water (W / O / W) emulsions, water-in-oil-in-oil (O / W / O) emulsions, and intra- and extra-chambered emulsions (small emulsions stabilizing large emulsions), can load hydrophilic and hydrophobic functional substances at different spatial locations due to their unique structure. Furthermore, the effective loading and controlled release of functional substances can be achieved by adjusting their size and structural position. Currently, domestic research on flavor-layering emulsions is limited to single materials or traditional protein-polysaccharide composite particles as raw materials. While some international research has explored multi-layered and multi-level emulsions stabilized by protein-polysaccharide composite particles, no reports have been published on novel intra- and extra-chambered emulsions with high internal phase density utilizing emulsion stabilization.

[0004] Therefore, the present invention provides a method for constructing flavorful high internal phase emulsions with an inner and outer cavity hierarchical structure using composite coagulated microemulsions. Summary of the Invention

[0005] The primary objective of this invention is to provide a method for preparing a flavorful internal phase emulsion with an inner and outer chamber hierarchical structure.

[0006] The second objective of this invention is to provide a flavor-enriched high internal phase emulsion with an inner and outer chamber hierarchical structure. This high internal phase emulsion exhibits more stable lipid oxidation stability during processing and storage, and has a better controlled release effect on flavor substances.

[0007] This invention provides a flavorful internal phase emulsion with inner and outer chambers, comprising the following steps:

[0008] S1. Construction of Level I Flavor Microemulsion: Zein-limonene flavor microemulsion stock solution was prepared by dissolving zein in an aqueous ethanol solution, adding D-limonene and emulsifier, and then preparing the stock solution by antisolvent method.

[0009] S2. Constructing a hierarchical type II external cavity coagulation microemulsion: Prepare a microcrystalline chitin mother liquor, mix the Zein-limonene microemulsion mother liquor prepared in S1 with the microcrystalline chitin mother liquor, and use LBL technology to form a Zein-limonene-CNCs composite coagulation microemulsion, and adjust the pH value of the composite coagulation microemulsion.

[0010] S3. Construction of a type III high internal phase emulsion with inner and outer cavities: Take the Zein-limonene-CNCs composite coagulated microemulsion prepared in S2, add flavor mixed oil, and homogenize by high-speed shearing to obtain a flavor high internal phase emulsion with inner and outer cavities.

[0011] Preferably, the specific steps of step S1 are as follows: dissolve zein in an aqueous ethanol solution, stir evenly at room temperature, add D-limonene, shear homogenize and emulsify, add emulsifier Span 80 for emulsification, and remove ethanol and some water by rotary evaporation to obtain Zein-limonene flavored microemulsion mother liquor.

[0012] Preferably, in step S1, the mass ratio of zein to D-limonene is 1-3:25-50.

[0013] Preferably, the preparation method of the microcrystalline chitin mother liquor in step S2 is as follows: chitin is dissolved in hydrochloric acid and stirred in a boiling water bath; after the water bath, centrifugation is performed, and the solid is obtained by suction filtration. The solid is washed with water and then filtered and centrifuged again. Deionized water is added to the precipitate and homogenized under high pressure; after homogenization, the microcrystalline chitin mother liquor is obtained.

[0014] Preferably, in step S2, the volume ratio of Zein-limonene flavored microemulsion mother liquor to microcrystalline chitosan mother liquor is 3:2.

[0015] Preferably, in step S2, the pH value of the composite coagulated microemulsion is adjusted to 6.5-7.5.

[0016] Preferably, the mass ratio of the Zein-limonene-CNCs composite coagulated microemulsion to the flavor blended oil in step S3 is 1:3-1:5.

[0017] Preferably, the flavor blend oil is at least one of diacetyl, 2-pentanone, 2-heptanone, and ethyl hexanoate.

[0018] Preferably, the high-speed shearing homogenization rate in step S3 is 8000-10000 rpm, and the homogenization time is 1-2 min.

[0019] The present invention also provides a flavorful internal phase emulsion with inner and outer chambers prepared by the above preparation method.

[0020] Beneficial effects:

[0021] This invention employs a composite coagulated microemulsion to construct a high-flavor internal phase emulsion with an inner and outer cavity layered structure. By utilizing the self-assembly properties of zein, D-limonene flavor oil is embedded during the desolventization process to construct a layered type I flavor microemulsion. This microemulsion is further combined with microcrystalline chitin through spontaneous interaction to form a layered type II coagulated microemulsion. Finally, the coagulated microemulsion is used to embed a mixture of four flavor oils—diacetyl, 2-pentanone, 2-heptanone, and ethyl hexanoate—to construct a layered type III high-flavor internal phase emulsion with an inner and outer cavity layered structure.

[0022] The flavorful internal phase emulsion obtained by this invention has good lipid oxidation stability, which helps to extend the product shelf life; it also has pH responsiveness and flavor controlled release effect, which can significantly reduce flavor loss. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of SEM observation of the hierarchical type I microemulsion and hierarchical type II composite coagulated microemulsion in Examples 1-2 and Comparative Example 1 of the present invention;

[0025] Figure 2 SEM structural images of the high-flavor internal phase emulsions of Examples 1-2 and Comparative Example 1 are shown.

[0026] Figure 3 This is a schematic diagram showing the primary oxide (POV) and secondary oxide (MDA) values ​​of the flavor-rich internal phase emulsions in Examples 1-2 and Comparative Example 1.

[0027] Figure 4 The graph shows the nonlinear fitting of the Harrison mathematical model for high-flavor internal phase emulsions. Detailed Implementation

[0028] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0031] Example 1

[0032] A flavorful high-internal-phase emulsion with inner and outer chambers, comprising the following steps:

[0033] S1. Construction of Level I Flavor Microemulsion: 1 g of zein was dissolved in 40 mL of 85% ethanol aqueous solution and stirred at 350 rpm for 1 h at room temperature to obtain a zein ethanol solution. 25 g of D-limonene (DL) was added to the solution, and the mixture was emulsified using a shear homogenizer at 10000 rpm to obtain a microemulsion. 0.1 wt% of Span 80 was added to the microemulsion with slow stirring at 300 rpm. The addition of Span 80 effectively prevented the aggregation and agglomeration of limonene. Then, 80 mL of deionized water was added to the microemulsion in a 40℃ water bath at a rate of 1 mL / min using a separatory funnel. After 90 min, the mixture was rotary evaporated to 100 mL at 40℃ and 85 rpm to remove ethanol and some water, yielding the Zein-limonene flavor microemulsion stock solution (ZDL).

[0034] S2. Constructing a hierarchical type II external cavity coagulation microemulsion:

[0035] Preparation of microcrystalline chitin stock solution: Dissolve 8g of chitin in 3M hydrochloric acid and stir in a boiling water bath for 1.5h. After the water bath, centrifuge at 6000r / min for 20min, filter to obtain solids, wash the solids twice with water, filter and centrifuge again, add 400mL of deionized water to the precipitate, and homogenize under high pressure at 30MPa for 5min. After homogenization, a microcrystalline chitin stock solution (CNCs) with a mass concentration of 20g / mL is obtained.

[0036] The Zein-limonene microemulsion mother liquor prepared by S1 was mixed with the microcrystalline chitosan mother liquor at a volume ratio of 3:2 and magnetically stirred for 15 minutes. The two were then used to form a Zein-limonene-CNCs composite coagulated microemulsion (ZDLCs) through LBL technology. The pH value of the composite coagulated microemulsion was adjusted to 6.5. The pH value needs to be adjusted before each use to ensure the accuracy of the pH value. The microemulsion was then placed in a refrigerator at 4°C for hydration and ready for use.

[0037] S3. Construction of a Type III flavor high internal phase emulsion: 3g of the Zein-limonene-CNCs composite coagulated microemulsion prepared in S2 was added to 12g of flavor mixed oil. The flavor mixed oil was a mixture of diacetyl, 2-pentanone, 2-heptanone, and ethyl hexanoate. The mass concentration of diacetyl in the MCT oil was 500-600 mg / L; the mass concentration of 2-pentanone in the MCT oil was 200-250 mg / L; the mass concentration of 2-heptanone in the MCT oil was 1000-1200 mg / L; and the mass concentration of ethyl hexanoate in the MCT oil was 2800-3000 mg / L. After high-speed shear homogenization at 8000 rpm for 1 min, a flavor high internal phase emulsion (ZDLCs-HIPEs) with an oil content of 80 wt% and having inner and outer chambers was obtained.

[0038] Example 2

[0039] A flavorful high-internal-phase emulsion with inner and outer chambers, comprising the following steps:

[0040] S1. Construction of Level I Microemulsion: 1.2 g of zein was dissolved in 40 mL of 85% ethanol aqueous solution and stirred at 350 rpm for 1 h at room temperature to obtain a zein ethanol solution. 20 g of D-limonene (DL) was added to the solution, and the mixture was emulsified using a shear homogenizer at 10000 rpm to obtain a microemulsion. 0.1 wt% of Span 80 was added to the microemulsion with slow stirring at 300 rpm. The addition of Span 80 effectively prevents limonene aggregation and agglomeration. Then, 80 mL of deionized water was added to the microemulsion in a 40°C water bath at a rate of 1 mL / min using a separatory funnel. After 90 min, the mixture was rotary evaporated to 100 mL at 40°C and 85 rpm to remove ethanol and some water, yielding the Zein-limonene microemulsion stock solution (ZDL).

[0041] S2. Constructing a hierarchical type II external cavity coagulation microemulsion:

[0042] Preparation of microcrystalline chitin stock solution: Dissolve 8g of chitin in 3M hydrochloric acid and stir in a boiling water bath for 1.5h. After the water bath, centrifuge at 6000r / min for 20min, filter to obtain solids, wash the solids twice with water, filter and centrifuge again, add 400mL of deionized water to the precipitate, and homogenize under high pressure at 30MPa for 5min. After homogenization, a microcrystalline chitin stock solution (CNCs) with a mass concentration of 20g / mL is obtained.

[0043] The Zein-limonene microemulsion mother liquor prepared in S1 was mixed with the microcrystalline chitosan mother liquor at a volume ratio of 3:2 and magnetically stirred for 15 minutes. The two were then used to form a Zein-limonene-CNCs composite coagulated microemulsion (ZDLCs) through LBL technology. The pH value of the composite coagulated microemulsion was adjusted to 7.5. The pH value needs to be adjusted before each use to ensure the accuracy of the pH value. The microemulsion was then placed in a refrigerator at 4°C for hydration and ready for use.

[0044] S3. Construction of a Type III flavor high internal phase emulsion: Take 3g of the Zein-limonene-CNCs composite microemulsion prepared in S2, and add 12g of flavor mixed oil. The flavor mixed oil is a mixture of diacetyl, 2-pentanone, 2-heptanone, and ethyl hexanoate. The mass concentration of diacetyl in the MCT oil is 500-600 mg / L; the mass concentration of 2-pentanone in the MCT oil is 200-250 mg / L; the mass concentration of 2-heptanone in the MCT oil is 1000-1200 mg / L; and the mass concentration of ethyl hexanoate in the MCT oil is 2800-3000 mg / L. After high-speed shear homogenization at 8000 rpm for 1 min, a flavor high internal phase emulsion (ZDLCs-HIPEs) with an oil content of 80 wt% and having inner and outer chambers is obtained.

[0045] Comparative Example 1

[0046] A single-compartment flavor high internal phase emulsion includes the following steps:

[0047] S1. Construction of Level I Flavor Microemulsion: 1.2 g of zein was dissolved in 40 mL of 85% ethanol aqueous solution and stirred at 350 rpm for 1 h at room temperature to obtain a zein ethanol solution. 20 g of D-limonene (DL) was added to the solution, and the mixture was emulsified using a shear homogenizer at 10000 rpm to obtain a microemulsion. 0.1 wt% of Span 80 was added to the microemulsion with slow stirring at 300 rpm. The addition of Span 80 effectively prevented the aggregation and agglomeration of limonene. Then, 80 mL of deionized water was added to the microemulsion in a 40°C water bath at a rate of 1 mL / min using a separatory funnel. After 90 min, the mixture was rotary evaporated to 100 mL at 40°C and 85 rpm to remove ethanol and some water, yielding the Zein-limonene flavor microemulsion stock solution (ZDL).

[0048] S2. Constructing a hierarchical type II external cavity coagulation microemulsion:

[0049] Preparation of microcrystalline chitin stock solution: Dissolve 8g of chitin in 3M hydrochloric acid and stir in a boiling water bath for 1.5h. After the water bath, centrifuge at 6000r / min for 20min, filter to obtain solids, wash the solids twice with water, filter and centrifuge again, add 400mL of deionized water to the precipitate, and homogenize under high pressure at 30MPa for 5min. After homogenization, a microcrystalline chitin stock solution (CNCs) with a mass concentration of 20g / mL is obtained.

[0050] The Zein-limonene microemulsion mother liquor prepared in S1 was mixed with the microcrystalline chitosan mother liquor at a volume ratio of 3:2 and magnetically stirred for 15 minutes. The two were then used to form a Zein-limonene-CNCs composite coagulated microemulsion (ZDLCs) through LBL technology. The pH value of the composite coagulated microemulsion was adjusted to 5.5. The pH value needs to be adjusted before each use to ensure the accuracy of the pH value. The microemulsion was then placed in a refrigerator at 4°C for hydration and ready for use.

[0051] S3. Construction of a Type III flavor high internal phase emulsion: 3g of the Zein-limonene-CNCs composite coagulated microemulsion prepared in S2 was added to 12g of flavor mixed oil. The flavor mixed oil was a mixture of diacetyl, 2-pentanone, 2-heptanone, and ethyl hexanoate. The mass concentration of diacetyl in the MCT oil was 500-600 mg / L; the mass concentration of 2-pentanone in the MCT oil was 200-250 mg / L; the mass concentration of 2-heptanone in the MCT oil was 1000-1200 mg / L; and the mass concentration of ethyl hexanoate in the MCT oil was 2800-3000 mg / L. After high-speed shear homogenization at 8000 rpm for 1 min, a single-chamber flavor high internal phase emulsion (ZDLCs-HIPEs) with an oil content of 80 wt% was obtained.

[0052] Microstructure observation:

[0053] The microstructure of layer I microemulsion and layer II external cavity coagulated microemulsion was observed using SEM: zein, ZDL prepared in step S1, and ZDLCs with different pH values ​​prepared in step S2 of Examples 1-2 and Comparative Example 1 were directly dropped onto tin foil attached to conductive adhesive and allowed to dry naturally.

[0054] Further observation of the core-shell structure of ZDL: The lyophilized ZDL powder was dispersed in acetone. DL is readily soluble in acetone, while Zein is insoluble. The microemulsion was then ultrasonically disrupted using an ultrasonic cell disruptor (2 min, 320 W, 3 s intervals). The solution was then centrifuged and washed with acetone at least three times to remove limonene as much as possible. Finally, the precipitate was dried in a fume hood. The microstructure of the sample was observed using a TESCAN MIRA SEM. The Zein obtained after removing DL with acetone and ultrasonically disrupting the microemulsion formed a core-shell structure, directly demonstrating that Zein, acting as a Pickering emulsifier, encapsulated the DL flavor oil, forming a hierarchical type I flavor microemulsion.

[0055] SEM images of zein, ZDL, and the zein core-shell structure are shown below. Figure 1 As shown in the first row, the Zein nanoparticles before encapsulation are at the nanoscale, and the solution is in a clear state. By adding D-limonene before rotary evaporation, a micron-scale Zein-D-limonene microemulsion (ZDL) was obtained. The figure shows a clear difference between the microemulsion formed on the upper layer of ZDL and the nanoparticles.

[0056] SEM images of ZDLCs at pH 5.5, 6.5 and 7.5 are shown below. Figure 1 As shown in the second line; positively charged CNCs were added based on LBL technology, further improving the stability of ZDL microemulsion; by Figure 1 The second line shows that CNCs are adsorbed onto the ZDL surface through electrostatic deposition to form ZDLCs aggregated microemulsions, forming a hierarchical type II aggregated microemulsion (ZDLCs).

[0057] SEM images of CNCs on the surface of ZDLCs at pH 5.5, 6.5, and 7.5 are shown below. Figure 1The third row shows a magnified view of the structure within the circle in the second row. It can be seen that CNCs on the surface aggregate under the influence of pH. Furthermore, the addition of CNCs and changes in pH also affect the macroscopic phenomena of ZDL. Since CNCs can interact with Zein, the addition of CNCs causes protein precipitation to disappear. Secondly, as the pH increases, the more negatively charged ZDL can undergo electrostatic neutralization with the positively charged CNCs, promoting the adsorption of more CNCs onto the ZDL surface, increasing the lipid encapsulation rate, and simultaneously reducing the overall net charge of ZDLCs, thus enhancing aggregation and improving the stability of the microemulsion.

[0058] SEM structural analysis of the high-flavor internal phase emulsions of Examples 1-2 and Comparative Example 1:

[0059] Characterization was performed using organic phase polymerization (cyclohexane and styrene). First, V65 polymerizer and styrene were mixed uniformly at a ratio of 1:100 (w / v). Then, the DL in Layer I was replaced with cyclohexane and styrene, and ethanol was rotary evaporated. Further, the flavor blend oil in Layer III was also replaced with cyclohexane and styrene. The styrene sample was diluted 10-fold with water and polymerized with shaking at 65°C for 24 h. Finally, the styrene and cyclohexane HIPEs were freeze-dried to remove moisture, and the layered structure of the samples was observed using a TESCAN MIRA SEM.

[0060] By replacing the oil phase with cyclohexane (CHX) and styrene (SM), the structure of ZDLCs-HIPEs can be observed. During the freeze-drying process, cyclohexane will volatilize and styrene will polymerize into a solid, which makes it easier to observe the structure of ZDLCs-HIPEs.

[0061] like Figure 2 (A) The SEM image of the oil phase, which is cyclohexane (CHX), shows an interwoven network structure, such as... Figure 2(B) The SEM image of the oil phase, styrene (SM), shows a solid, flattened spherical structure. For the cyclohexane sample, at the same magnification, the pore size decreases significantly with increasing pH. Further magnification in the second row shows that the aggregated layer at pH 5.5 is "filamentous," while at pH 6.5 and 7.5 it appears as a thick sheet. This differs from the thick, network-like structure formed by monolayer HIPEs stabilized solely by the Zein-CNCs composite; clearly, the network structure formed by ZDLCs-HIPEs is clearer. For the styrene sample, spherical structures of varying sizes appear. ZDLCs form micron-sized spheres (circled in the first row), while HIPEs form larger micron-sized spheres. For the pH 5.5 sample, the HIPEs have a larger particle size, and the ZDLC spheres are scattered in the blank areas. For the pH 6.5 and 7.5 samples, the flattened ZDLC spheres are observed to aggregate onto a single large sphere. On the one hand, this indicates that a hierarchical structure cannot be formed under pH 5.5 conditions, resulting in a single-cavity structure, while a hierarchical structure with both inner and outer cavities can be formed under pH 6.5 and 7.5 conditions. On the other hand, the hierarchical emulsion exhibits a completely different pattern from the monolayer HIPEs stabilized solely by Zein-CNCs, which only present single large spheres. All these results demonstrate that Examples 1-2 successfully constructed a novel HIPE with a hierarchical structure with both inner and outer cavities using ZDLCs.

[0062] Primary oxide (POV) determination:

[0063] Freshly prepared flavor high internal phase emulsions (ZDLCs-HIPPEs) from Examples 1-2 and Comparative Example 1 were aliquoted into 50 mL centrifuge tubes and incubated in a 50 °C oven to accelerate oil oxidation while in the dark. At different time intervals, 0.3 mL of the sample was added to 1.5 mL of isooctane-isopropanol mixture (3:1, v / v), vortexed, and centrifuged at 1000 g for 2 min. This process was repeated three times. Then, 0.2 mL of the supernatant organic phase was taken, and 2.8 mL of methanol-n-butanol mixture (2:1, v / v) was added. 15 μL of 3.94 M potassium thiocyanate, 7.5 μL of 0.132 M barium chloride, and 7.5 μL of 0.144 M ferrous sulfate were rapidly added. After reacting in the dark for 20 min, the absorbance at 510 nm was measured using a UV spectrophotometer.

[0064] The content of hydrogen peroxide, a primary metabolite, was calculated using the hydrogen peroxide standard curve y = 0.0015x + 0.0151 (R² = 0.99). All reagents were prepared fresh and used immediately, and the measurements were performed in triplicate.

[0065] The primary oxide (POV) values ​​of the flavor-rich internal phase emulsions obtained in Examples 1-2 and Comparative Example 1 are as follows: Figure 3As shown in (A). The overall POV values ​​are relatively small. In addition, the POVs of ZDLCs-HIPPEs at pH 6.5 and 7.5 are significantly smaller than those of ZDLCs-HIPPEs at pH 5.5 within 15 days. The products of Examples 1-2 have higher oxidative stability.

[0066] Determination of secondary oxide (MDA):

[0067] A suitable amount of the fresh emulsions obtained in Examples 1-2 and Comparative Example 1 were transferred to samples and placed in a dark oven at 50°C for 15 days. Samples were collected on days 1 and 15. 0.2 mL of the emulsion was vortexed with 5 mL of a mixed reagent (15 g trichloroacetic acid, 0.375 g thiobarbituric acid, and 1.76 mL 12 M hydrochloric acid dissolved in 82.9 mL of water), heated in a boiling water bath for 15 min, then cooled to room temperature in a running water bath, and finally centrifuged at 4000 rpm for 15 min. The absorbance of the supernatant was measured at 532 nm using a UV spectrophotometer. The MDA value of the emulsion was calculated based on the standard curve of 1,1,3,3-tetraethoxypropane: y = 75.9062x + 0.0032 (R² = 0.999).

[0068] The secondary oxide (MDA) values ​​of the flavor-rich internal phase emulsions obtained in Examples 1-2 and Comparative Example 1 are as follows: Figure 3 As shown in (B), the test results for each set of examples, from left to right, represent the MDA values ​​for day 1 and day 15, where lowercase letters and * indicate significant differences (P<0.05). The MDA values ​​of ZDLCs-HIPPEs at pH 6.5 and 7.5 on day 1 and day 15 were significantly lower than the MDA value of ZDLCs-HIPPEs at pH 5.5, indicating that the products of Examples 1-2 exhibit higher oxidative stability.

[0069] This improved oxidative stability is mainly attributed to two aspects: firstly, the dense interfacial layer formed by the Zein / CNCs aggregates scavenges free radicals and prevents contact between oil and O2 molecules; secondly, the increased emulsion viscosity in the presence of the microcrystalline chitin zygotic structure can inhibit the movement of oxidative free radicals and metal ions, thereby achieving higher oxidative stability.

[0070] Static headspace analysis:

[0071] Two g of the flavor high internal phase emulsions (ZDLCs-HIPEs) prepared in Examples 1-2 and Comparative Example 1 were aspirated into a 20 mL headspace gas chromatograph, immediately capped and sealed, and stored at 4°C for 24 h to ensure flavor equilibrium. In the formal experiment, the gas chromatograph was placed in an Agilent 7690A headspace sample chamber and equilibrated at 60°C for 6 min. The instrument automatically aspirated 1 μL of headspace air from the bottle and injected it into an Agilent 7898B gas chromatograph for measurement. Gas chromatography was performed using an HP-5 capillary column (30 m, 0.32 mm inner diameter, 0.25 mm film thickness) equipped with a flame ionization detector (FID). The nitrogen carrier gas flow rate was 1.4 mL / min in split mode (15:1). The injector and FID temperatures were both 250°C. The temperature program was: 65℃ (0.5 min) to 180℃ (15℃ / min, 0.2 min), and the partition coefficient (K) in the gas phase and emulsion was... A / E ), calculated according to Formula 1:

[0072]

[0073] Where C A C represents headspace flavor concentration. E This refers to the concentration of the emulsion flavor.

[0074] Table 1 shows that Examples 1-2 and Comparative Example 1 used different pH values ​​to affect compound K in ZDLCs-HIPEs. A / E (×10 4 The impact of ).

[0075] Table 1

[0076]

[0077]

[0078] This invention employs five flavors with different hydrophilicity and hydrophobicity: diacetyl (C4, Log P = -1.43), pentanone (C5, Log P = 0.91), heptanone (C7, Log P = 1.97), ethyl hexanoate (C8, Log P = 2.83), and D-limonene (C8, Log P = 4.43). The most hydrophobic D-limonene is located in the outer cavity, while diacetyl, pentanone, heptanone, and ethyl hexanoate are located in the inner cavity. As shown in Table 1, the affinity of D-limonene in the outer cavity decreases significantly with increasing pH. This is mainly due to the "conjoined structure" of CNCs electrostatically deposited on the surface of the ZDL emulsion. This structure hinders flavor volatilization and promotes the adsorption of more Zein at the oil-water interface, forming a tight ZDLCs structure. D-limonene can interact and bind with more Zein, which retains some flavor release, thus reducing the K of D-limonene.A / E The value decreased with increasing pH. For the four flavors with significant differences in hydrophilicity and hydrophobicity within the cavity, there were significant differences in affinity between samples at pH 5.5 (single cavity) and pH 6.5 and 7.5 (inner and outer cavities). This clearly demonstrates the formation of complex aggregates and the differences between the inner and outer cavity structures and the single cavity structure. Compared to the single cavity at pH 5.5, the aggregates were more and more firmly adsorbed at the oil-water interface; therefore, Zein could expose more hydrophobic points to interact with flavor compounds, thus also leading to K... A / E The value decreases. Furthermore, the condensation of the outer cavity within the inner cavity helps to hinder the release of flavor.

[0079] Dynamic headspace analysis:

[0080] Before the measurement, artificial saliva was prepared with the following formula: KCl (0.9 g / L), NaSCN (0.17 g / L), KH2PO4 (1.0 g / L), Na2SO4 (1.3 g / L), NaHCO3 (1.7 g / L), NaCl (0.3 g / L), CaCl2 (0.11 g / L), urea (0.2 g / L), and mucin (0.025 g / L). The powders were mixed into a pH 7.2 PBS solution and stirred thoroughly. For the formal measurement, 10 g of the flavor high internal phase emulsions (ZDLCs-HIPPEs) obtained in Examples 1-2 and Comparative Example 1, and 10 mL of artificial saliva were added to a self-made oral and nasal cavity model device (volume 210 mL, height 12.5 cm) that was pre-equilibrated in a 37°C water bath. A rotor was then placed inside, and the device was quickly sealed with a sealing film. Throughout the test, the model was maintained at 37°C through water bath circulation. Stir with a magnetic stirrer at 250 rpm. At each test time, headspace gas (1.0 mL) was extracted from the model using a 2.5 mL isothermal SGEGC syringe (Trajan Science Australia Pty Ltd, Australia) and rapidly injected into the inlet of the Agilent 7890B gas chromatograph.

[0081] Mathematical Model for Aroma Release Theory: The mathematical model describing aroma release can be interpreted using the mathematical model previously developed by Harrison et al., which describes the release of flavor from aqueous solutions containing flavor-binding polymers. This model utilizes Equation 2, which assumes that the transport of volatile substances across the gas-liquid interface can be described by the osmosis theory of interfacial mass transfer.

[0082]

[0083] Among them, c g (t) represents the concentration released (mg.cm³) over time t. -3 ), c e(0) indicates the initial flavor concentration (mg.cm). -3 ), K ge v is the allocation coefficient. g and v e The values ​​are expressed as flavor and solution volume (cm²), respectively. 3 ), h D The interfacial mass transfer coefficient (ms) -1 ), A ge Expressed as gas-liquid contact area (cm²) 2 ).

[0084] The nonlinear fitting plot of the Harrison mathematical model for flavored hippes is shown below. Figure 4 As shown, the components include D-limonene (A); diacetyl (B); 2-pentanone (C); 2-heptanone (D); and ethyl hexanoate (E).

[0085] The predicted flavor concentrations (Ct) of flavored hippes at pH 5.5, 6.5, and 7.5 as t→∞ were obtained based on the Harrison mathematical model fitting. g (∞)), release rate (v(t)), mass transfer coefficient (h) D ) and correlation coefficient (R 2 As shown in Table 2.

[0086] Table 2

[0087]

[0088]

[0089] In this invention, a self-made oral device is used to add artificial saliva and continuously mechanically stir at 37°C to simulate the stirring process of the mouth and tongue. Head air is periodically extracted from the sample to simulate nasal reception, achieving real-time monitoring of flavor release. To further understand the flavor release mechanism and influencing factors, the mathematical model proposed by Harrison et al. is used to compare flavor release. The results are as follows: Figure 4As shown in Table 2, the correlation coefficients of the flavor HIPPEs at different flavors and pH values ​​are all greater than 0.97, indicating the reliability of the data. For the release of limonene from the outer cavity, Cg(∞) increases significantly with increasing pH as t→∞, while the flavor release rate and mass transfer coefficient decrease accordingly. This is because CNCs adsorb onto the ZDL surface, and due to the "conjoined structure" of the CNCs, the condensed layer gradually thickens and becomes denser, effectively hindering flavor release and achieving the purpose of long-term storage and controlled release of flavor. For the release of flavors with different hydrophilicity and hydrophobicity in the inner cavity, regardless of hydrophilicity or hydrophobicity, the general rule is that with increasing pH, Cg(∞) increases, while the flavor release rate and mass transfer coefficient decrease. This rule fully demonstrates that the hierarchical structure has a significant effect on flavor controlled release. Due to the dense outer cavity condensed microemulsion on the outer cavity surface, less flavor is released into the air more slowly, effectively preventing flavor loss.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a flavorful internal phase emulsion with inner and outer chambers, characterized in that, Includes the following steps: S1. Construction of Level I Flavor Microemulsion: Zein-limonene flavor microemulsion stock solution was prepared by dissolving zein in an aqueous ethanol solution, adding D-limonene and emulsifier, and then preparing the stock solution by antisolvent method. The specific steps are as follows: dissolve zein in an ethanol aqueous solution, stir evenly at room temperature, add D-limonene, shear homogenize and emulsify, add emulsifier Span 80 for emulsification, and remove ethanol and some water by rotary evaporation to obtain Zein-limonene flavored microemulsion mother liquor; the mass ratio of zein to D-limonene is 1-3:25-50. S2. Construction of a hierarchical type II external cavity coagulated microemulsion: Prepare a microcrystalline chitosan stock solution, mix the Zein-limonene flavored microemulsion stock solution prepared in S1 with the microcrystalline chitosan stock solution, the volume ratio of the Zein-limonene flavored microemulsion stock solution to the microcrystalline chitosan stock solution is 1:2-3:1; use LBL technology to form a Zein-limonene-CNCs composite coagulated microemulsion, adjust the pH value of the composite coagulated microemulsion to 6.5-7.5; S3. Constructing a type III high-flavor internal phase emulsion: Take the Zein-limonene-CNCs composite coagulated microemulsion prepared in S2, add flavor mixed oil, the mass ratio of Zein-limonene-CNCs composite coagulated microemulsion to flavor mixed oil is 1:3-1:5, and after high-speed shear homogenization, a high-flavor internal phase emulsion with inner and outer chambers is obtained.

2. The method for preparing a flavorful internal phase emulsion with inner and outer chambers according to claim 1, characterized in that, The preparation method of the microcrystalline chitin mother liquor in step S2 is as follows: Chitin is dissolved in hydrochloric acid and stirred in a boiling water bath; after the water bath, centrifugation is performed, and the solid is obtained by suction filtration. The solid is washed with water and then filtered and centrifuged again. Deionized water is added to the precipitate and homogenized under high pressure; after homogenization, microcrystalline chitin mother liquor is obtained.

3. The method for preparing a flavorful internal phase emulsion with inner and outer chambers according to claim 1, characterized in that, The flavor blend oil is at least one of diacetyl, 2-pentanone, 2-heptanone, and ethyl hexanoate.

4. The method for preparing a flavorful internal phase emulsion with inner and outer chambers according to claim 1, characterized in that, In step S3, the high-speed shearing homogenization rate is 8000-10000 rpm, and the homogenization time is 1-2 min.

5. A flavorful internal phase emulsion with inner and outer chambers prepared by any one of the preparation methods of claims 1-4.

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