Method for preparing controllable release garlic essential oil microcapsules by high-voltage electrostatic field-ultrasonic assistance

Abstract

The application discloses a method for preparing garlic essential oil microcapsules with controllable release by means of high-voltage electrostatic field-ultrasonic assistance, and belongs to the technical field of food processing and preservation. The application adopts a high-voltage electrostatic field combined with ultrasonic assistance to prepare whey protein-arabic gum composite wall material microcapsules by means of a complex coagulation method, and then realizes stable embedding and controllable release of garlic essential oil through enzyme cross-linking and drying processes. Through the synergistic effect of high-voltage electrostatic field, ultrasonic assistance and enzyme cross-linking, the application breaks through the randomness of the traditional complex coagulation process, and realizes accurate regulation of the compactness and thickness of the microcapsule wall structure. The obtained microcapsules have high embedding rate (greater than 90%) and intelligent release characteristics, and the stability and application value of the garlic essential oil are improved.

Description

Technical Field

[0001] This invention belongs to the field of food processing and preservation technology, specifically relating to a method for preparing controllable release garlic essential oil microcapsules with the assistance of a high-voltage electrostatic field and ultrasound. Background Technology

[0002] Garlic oil, extracted from garlic, is a volatile oil with broad-spectrum antibacterial and antioxidant activities, showing great promise for applications in food preservation and health products. However, its strong, pungent odor, chemical instability, and volatility significantly limit its applications. Microencapsulation technology is an effective strategy for protecting these sensitive active ingredients, masking unpleasant flavors, and achieving controlled release.

[0003] Traditional microencapsulation technologies, such as spray drying and complex coagulation, have been widely used, but they still suffer from problems such as low encapsulation efficiency, limited release behavior (mostly burst release or slow diffusion), and difficulty in responding to specific environmental triggers for release. For example, complex coagulation relies on the electrostatic interaction of the wall material, but the process is difficult to control precisely, resulting in microcapsule structures with varying density and unpredictable release behavior.

[0004] Existing technologies, such as CN112220086A, disclose "a garlic essential oil microcapsule and its preparation method," which uses gelatin and gum arabic to prepare microcapsules via complex coagulation. However, this method does not precisely control the release behavior, and the microcapsules are prone to early leakage during storage, and cannot achieve directional and timed release. Therefore, developing a new method that can precisely control the microcapsule structure and achieve intelligent and controllable release of garlic essential oil has significant practical implications. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing controllable-release garlic essential oil microcapsules using a high-voltage electrostatic field-ultrasound assisted process. This method introduces a high-voltage electrostatic field combined with ultrasound intervention into the traditional complex coagulation process, precisely controlling the crosslinking and deposition behavior of the wall material to prepare garlic essential oil microcapsules with a clear core-shell structure, dense wall layers, and tunable release behavior. These microcapsules effectively protect the core material and can achieve controllable release based on ambient humidity or mechanical pressure.

[0006] The technical solution of the present invention: A method for preparing controllably releasing garlic essential oil microcapsules using a high-voltage electrostatic field-ultrasound assisted process, comprising the following main steps: (1) Preparation of wall material solution: Dissolve whey protein in deionized water and stir to hydrate to obtain whey protein solution; dissolve gum arabic in deionized water and stir to dissolve to obtain gum arabic solution; mix the whey protein solution and gum arabic solution evenly to form whey protein-gum arabic composite wall material solution; (2) Preparation of emulsion: Garlic essential oil and the isolated whey protein-gum arabic composite wall material solution prepared in step (1) are mixed according to a fixed core material and wall material mass ratio, and primary emulsification is carried out using a high-speed shear machine, followed by fine emulsification using a high-pressure homogenizer to obtain a stable O / W type emulsion. (3) High voltage electrostatic field combined with ultrasound-assisted coagulation: The pH value of the O / W type emulsion obtained in step (2) was adjusted to 4.0 with 1% hydrochloric acid solution to induce coagulation of isolated whey protein and gum arabic; this coagulated solution was placed in a high voltage electrostatic field combined with ultrasound reaction device and reacted under a specific electric field and ultrasound intensity, so that the positively charged isolated whey protein and the negatively charged gum arabic moved in a direction, cross-linked and encapsulated garlic essential oil under the drive of electric field force, forming a more regular microcapsule product; (4) Curing and cross-linking: Add transglutaminase to the aqueous solution of the microcapsule product obtained in step (3) for enzymatic cross-linking, while slowly cooling to 4 ℃ and completing curing in 12 h to strengthen the capsule wall structure. (5) Washing and drying: The solidified microcapsules are washed with 10-30% ethanol and spray-dried to obtain the dried garlic essential oil controlled release microcapsule product.

[0007] In step (1), the mass ratio of whey protein to gum arabic is 4:1 to 4:2, and the total concentration of the composite wall material is 1% to 3% (w / v).

[0008] In step (2), the core-wall mass ratio, i.e., the ratio of whey protein-gum arabic composite wall material to garlic essential oil, is 4:1 to 2:1; the high-speed shearing conditions are 1000 to 2000 rpm for 2 to 5 min; the high-pressure homogenization conditions are 30 to 50 MPa, and the high-pressure homogenization cycle is 2 to 3 times.

[0009] The intensity range of the high voltage electrostatic field in step (3) is 10~25 kV / cm, the processing time is 20~60 min, and the processing temperature is 40~50 ℃.

[0010] The power range of the ultrasound in step (3) is 40~80 W, and the processing time is 20~60 min.

[0011] In step (4), the amount of transglutaminase added is 20~40 U / g protein, the cross-linking temperature is 45~50 ℃, and the time is 1~2 h.

[0012] Step (5) The inlet temperature of the spray dryer is 120-160 ℃, the outlet temperature is 70-100 ℃, and the flow rate is 12-18 mL / min.

[0013] The garlic essential oil microcapsules prepared according to the above method are characterized in that the encapsulation rate of the microcapsules is not less than 90%, and they exhibit intelligent release characteristics of gastric sustained release (release rate <20% in 2 hours) and intestinal targeted release (release rate >70% in the subsequent 2 hours) in a simulated gastrointestinal environment.

[0014] This invention provides a method for preparing controllable-release garlic essential oil microcapsules using a high-voltage electrostatic field-ultrasound-assisted process. The high-voltage electrostatic field, combined with ultrasound-assisted separation, directionally encapsulates garlic essential oil using a whey protein-gum arabic composite wall material, forming a dense and uniformly distributed microcapsule wall. This effectively prevents direct contact between the core material and the external environment, preventing the volatilization and oxidation of the garlic essential oil. The selection and design of a specific ratio of composite wall material imparts environmentally responsive characteristics to the microcapsules, enabling controllable release of the core material. Enzyme cross-linking technology further enhances the mechanical strength and stability of the capsule wall, and the hydrophilicity of gum arabic allows for swelling under high humidity conditions, further regulating the release rate of the core material. The combination of high-voltage electrostatic field and ultrasound not only precisely controls the morphology and structure of the microcapsules but also improves encapsulation efficiency and oil loading capacity. Furthermore, by adjusting the intensity and processing parameters of the electrostatic field and ultrasound, the thickness and density of the capsule wall can be precisely designed, thereby achieving intelligent and controllable release of garlic essential oil. Therefore, this invention combines high-voltage electrostatic field with ultrasound, composite coagulation and enzymatic cross-linking technology to synergistically improve the stability of garlic essential oil, mask its unpleasant flavor, and achieve its directional and timed release in different application scenarios, greatly expanding the application value of garlic essential oil in food, medicine and other fields.

[0015] The beneficial effects of this invention compared to the prior art are as follows: (1) Controllable release behavior: By precisely controlling the complex coagulation process through a high-voltage electrostatic field combined with ultrasound, microcapsules with different wall thicknesses and densities can be prepared. Microcapsules formed under low field strength have relatively loose walls, which are easily triggered by mechanical forces (such as chewing) during processing, exhibiting the characteristic of "pressure-controlled release". Microcapsules formed under a high-voltage electrostatic field combined with ultrasound have dense walls, which can effectively resist mechanical forces, but gum arabic absorbs moisture and swells in high humidity environments, which can achieve "humidity-controlled release". This realizes a leap from "slow diffusion" to "intelligent response".

[0016] (2) Significantly improved embedding rate and efficiency: The high voltage electrostatic field combined with ultrasound promotes the more efficient aggregation and deposition of wall material molecules with opposite charges around the oil droplets, reducing the ineffective self-aggregation of the wall material, so that the embedding rate can be increased to more than 90% and the oil loading capacity exceeds 30%.

[0017] (3) More regular structure and enhanced stability: The microcapsules formed by high voltage electrostatic field combined with ultrasound induction are more uniform in size, have better sphericity, clear core-shell structure, and continuous and dense wall layer, which significantly improves the stability of the product during storage and slows down the oxidation and volatilization of the core material.

[0018] (4) Green and energy-saving: High voltage electrostatic field and ultrasound are physical field technologies, which do not require the addition of a large amount of chemical cross-linking agents (such as glutaraldehyde). The process is mild and environmentally friendly, which is in line with the clean label trend of modern food industry. Attached Figure Description

[0019] Figure 1 Encapsulation rates of different treatment groups; Figure 2 Odor analysis of different treatment groups after storage. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0021] Example 1 A method for preparing controllably released garlic essential oil microcapsules with high-voltage electrostatic field-ultrasound assistance includes the following steps: (1) Dissolve 1g of isolated whey protein in 100 mL of deionized water, stir and hydrate to obtain a 1% analytical whey protein solution; dissolve 1g of gum arabic in 100 mL of deionized water, stir and dissolve to obtain a 1% solution; mix the two solutions at a ratio of 4:1 and hydrate in a refrigerator at 5 ℃ for 12 h to form an isolated whey protein-gum arabic composite wall material solution; (2) The whey protein-gum arabic prepared in step (1) was mixed with garlic essential oil at a mass ratio of 4:1. The mixture was sheared for 3 minutes using a high-speed shearing machine at 1000 rpm to obtain primary emulsification. Then, it was homogenized twice using a high-pressure homogenizer at 30 MPa to obtain fine emulsification, resulting in a stable O / W type emulsion. (3) The pH of the emulsion obtained in step (2) was adjusted to 4.0 with 1% hydrochloric acid solution to induce the re-aggregation of isolated whey protein and gum arabic. This system was placed in a 10 kV / cm high-voltage electrostatic field combined with a 40W ultrasonic reaction device for 20 min at a temperature of 40 ℃, so that the positively charged isolated whey protein and the negatively charged gum arabic could move directionally, cross-link and encapsulate oil droplets under the drive of the electric field, forming a more regular microcapsule initial product; (4) Add 20 U / g transglutaminase to the microcapsule suspension obtained in step (3) to perform enzyme cross-linking, and at the same time slowly cool down to strengthen the capsule wall structure. (5) The microcapsule cured in step (4) was washed twice with 10% ethanol and dried by spray drying to obtain dried microcapsule powder. The inlet temperature of the spray dryer was 120 ℃, the outlet temperature was 70 ℃, and the flow rate was 12 mL / min.

[0022] Example 2 (1) Dissolve 2g of isolated whey protein in 100 mL of deionized water, stir and hydrate to obtain a 2% analytical whey protein solution; dissolve 2g of gum arabic in 100 mL of deionized water, stir and dissolve to obtain a 2% solution; mix the two solutions at a ratio of 4:1.5 and hydrate in a refrigerator at 5 ℃ for 12 h to form an isolated whey protein-gum arabic composite wall material solution; (2) The whey protein-gum arabic prepared in step (1) was mixed with garlic essential oil at a mass ratio of 4:2. The mixture was sheared for 4 min using a high-speed shearing machine at 1500 rpm to obtain primary emulsification. Then, it was homogenized three times using a high-pressure homogenizer at 40 MPa to obtain fine emulsification and a stable O / W type emulsion. (3) The pH of the emulsion obtained in step (2) was adjusted to 4.0 with 1% hydrochloric acid solution to induce the re-aggregation of isolated whey protein and gum arabic. This system was placed in a 20 kV / cm high-voltage electrostatic field combined with a 60W ultrasonic reaction device for 40 min at a temperature of 45 ℃, so that the positively charged isolated whey protein and the negatively charged gum arabic could move directionally, cross-link and encapsulate oil droplets under the drive of the electric field, forming a more regular microcapsule initial product; (4) Add 30 U / g transglutaminase to the microcapsule suspension obtained in step (3) to perform enzyme cross-linking, and at the same time slowly cool down to strengthen the capsule wall structure. (5) The microcapsules solidified in step (4) are washed twice with 20% ethanol and dried by spray drying to obtain dried microcapsule powder. The inlet temperature of the spray dryer is 140 ℃, the outlet temperature is 80 ℃, and the flow rate is 14 mL / min.

[0023] Example 3 A method for preparing controllable release microcapsules of garlic essential oil using a high-voltage electrostatic field assisted process includes the following steps: (1) Dissolve 3g of isolated whey protein in 100 mL of deionized water, stir and hydrate to obtain a 3% analytical whey protein solution; dissolve 3g of gum arabic in 100 mL of deionized water, stir and dissolve to obtain a 3% solution; mix the two solutions in a ratio of 4:2 and hydrate in a refrigerator at 5 ℃ for 12 h to form an isolated whey protein-gum arabic composite wall material solution; (2) The whey protein-gum arabic prepared in step (1) was mixed with garlic essential oil at a mass ratio of 4:1.5. The mixture was sheared for 5 min using a high-speed shearing machine at 2000 rpm to obtain primary emulsification. Then, it was homogenized three times using a high-pressure homogenizer at 50 MPa to obtain fine emulsification and a stable O / W type emulsion. (3) The pH of the emulsion obtained in step (2) was adjusted to 4.0 with 1% hydrochloric acid solution to induce the re-aggregation of isolated whey protein and gum arabic. This system was placed in a 30 kV / cm high-voltage electrostatic field combined with an 80W ultrasonic reaction device for 60 min at a temperature of 50 ℃, so that the positively charged isolated whey protein and the negatively charged gum arabic could move directionally, cross-link and encapsulate oil droplets under the drive of the electric field, forming a more regular microcapsule primary product; (4) Add 40 U / g transglutaminase to the microcapsule suspension obtained in step (3) to perform enzyme cross-linking, and at the same time slowly cool down to strengthen the capsule wall structure. (5) The microcapsules solidified in step (4) were washed twice with 15% ethanol and spray-dried to obtain dried microcapsule powder. The inlet temperature of the spray dryer was 160 ℃, the outlet temperature was 90 ℃, and the flow rate was 18 mL / min.

[0024] Compare with Example 1 (1) Dissolve 1g of isolated whey protein in 100 mL of deionized water, stir and hydrate to obtain a 1% analytical whey protein solution; dissolve 1g of gum arabic in 100 mL of deionized water, stir and dissolve to obtain a 1% solution; mix the two solutions at a ratio of 4:1 and hydrate in a refrigerator at 5 ℃ for 12 h to form an isolated whey protein-gum arabic composite wall material solution; (2) The whey protein-gum arabic prepared in step (1) was mixed with garlic essential oil at a mass ratio of 4:1. The mixture was sheared for 3 minutes using a high-speed shearing machine at 1000 rpm to obtain primary emulsification. Then, it was homogenized twice using a high-pressure homogenizer at 30 MPa to obtain fine emulsification, resulting in a stable O / W type emulsion. (3) The microcapsules obtained in step (2) were washed twice with 10% ethanol and dried by spray drying to obtain dried microcapsule powder. The inlet temperature of the spray dryer was 120 ℃, the outlet temperature was 70 ℃, and the flow rate was 12 mL / min.

[0025] Compare with Example 2 (1) Dissolve 1g of isolated whey protein in 100 mL of deionized water, stir and hydrate to obtain a 1% analytical whey protein solution; dissolve 1g of gum arabic in 100 mL of deionized water, stir and dissolve to obtain a 1% solution; mix the two solutions at a ratio of 4:1 and hydrate in a refrigerator at 5 ℃ for 12 h to form an isolated whey protein-gum arabic composite wall material solution; (2) The whey protein-gum arabic prepared in step (1) was mixed with garlic essential oil at a mass ratio of 4:1. The mixture was sheared for 3 minutes using a high-speed shearing machine at 1000 rpm to obtain primary emulsification. Then, it was homogenized twice using a high-pressure homogenizer at 30 MPa to obtain fine emulsification, resulting in a stable O / W type emulsion. (3) The pH of the emulsion obtained in step (2) was adjusted to 4.0 with 1% hydrochloric acid solution to induce the re-aggregation of isolated whey protein and gum arabic. This system was placed in a 10 kV / cm high-voltage electrostatic field combined with a 40W ultrasonic reaction device for 20 min at a temperature of 40 ℃, so that the positively charged isolated whey protein and the negatively charged gum arabic could move directionally, cross-link and encapsulate oil droplets under the drive of the electric field, forming a more regular microcapsule initial product; (4) The microcapsules solidified in step (3) were washed twice with 10% ethanol and dried by spray drying to obtain dried microcapsule powder. The inlet temperature of the spray dryer was 120 ℃, the outlet temperature was 70 ℃, and the flow rate was 12 mL / min.

[0026] Compare with Example 3 (1) Dissolve 1g of isolated whey protein in 100 mL of deionized water, stir and hydrate to obtain a 1% analytical whey protein solution; dissolve 1g of gum arabic in 100 mL of deionized water, stir and dissolve to obtain a 1% solution; mix the two solutions at a ratio of 4:1 and hydrate in a refrigerator at 5 ℃ for 12 h to form an isolated whey protein-gum arabic composite wall material solution; (2) The whey protein-gum arabic prepared in step (1) was mixed with garlic essential oil at a mass ratio of 4:1. The mixture was sheared for 3 minutes using a high-speed shearing machine at 1000 rpm to obtain primary emulsification. Then, it was homogenized twice using a high-pressure homogenizer at 30 MPa to obtain fine emulsification, resulting in a stable O / W type emulsion. (3) Adjust the pH of the emulsion obtained in step (2) to 4.0 with 1% hydrochloric acid solution to induce the re-aggregation of whey protein and gum arabic.

[0027] (4) Add 20 U / g transglutaminase to the microcapsule suspension obtained in step (3) to perform enzyme cross-linking, and at the same time slowly cool down to strengthen the capsule wall structure. (5) The microcapsules from step (4) were washed twice with 10% ethanol and then spray-dried to obtain dried microcapsule powder. The inlet temperature of the spray dryer was 120 °C, the outlet temperature was 70 °C, and the flow rate was 12 mL / min.

[0028] Experimental measurement method: 1. Determination of encapsulation efficiency To extract garlic essential oil from the surface of microcapsules, 0.5 g of the microcapsule sample was mixed with 10 mL of ethanol and stirred for 30 min. Subsequently, it was centrifuged at 8000 rpm for 10 min to obtain the garlic essential oil from the microcapsule surface. Another 0.5 g microcapsule sample was mixed with 10 mL of ethanol and sonicated at 500 W for 30 min to extract all the essential oil. After extraction, it was centrifuged at 8000 rpm for 10 min. Two more extraction cycles were performed to ensure complete extraction of essential oil from the microcapsules. The extracted surface essential oil and total essential oil solutions were diluted with ethanol to appropriate concentrations and then analyzed at the corresponding wavelengths (garlic essential oil, 330 nm, R). 2 The encapsulation efficiency of garlic essential oil was determined by a spectrophotometer at y = 0.99, y = 0.2086x + 0.1725.

[0029] 2. Electronic nose analysis The volatility of microcapsules and garlic essential oil was evaluated using an electronic nose. First, a 0.5 g sample was placed in a 20 mL plastic container and allowed to stand at 45 °C for 12 h before testing. The test parameters were as follows: headspace flow rate 1.0 L / min, test duration 360 seconds, and washout time 360 ​​seconds.

[0030] 3. Simulating the release of garlic essential oil in a gastrointestinal environment The microcapsules (1 g) were mixed with 7.5 mL of gastric juice in hydrochloric acid, followed by the addition of pepsin solution (1.6 mL, resulting in a final gastric juice concentration of 2000 U / mL), 0.3 M calcium chloride (5 μL), 1 M hydrochloric acid (0.2 mL), and distilled water (0.695 mL). The mixture was shaken at 100 rpm and 37 °C for 120 minutes on a temperature-controlled shaker, maintaining the pH at 3.0. Samples were taken at 30-minute intervals, and the release of garlic essential oil was determined.

[0031] The digestive mixture obtained from the gastric digestion stage was mixed with 11 mL of intestinal solution, followed by the sequential addition of 5 mL of pancreatic enzyme solution (100 U / mL in the final intestinal fluid), 0.25 mL of bile extract (10 mM), 40 μL of calcium chloride (0.3 M), 0.15 mL of sodium hydroxide (1 M), and 1.31 mL of distilled water. The mixture was then incubated on a constant-temperature shaker at 100 rpm and 37 °C for 120 min, with the pH maintained at 7.0. Samples were taken at 30-minute intervals, and the release of garlic essential oil was determined.

[0032] A comparison of indicators was made between controllable-release microcapsules of garlic essential oil prepared using different processing methods. Figure 1 and Figure 2The effects of different treatments on encapsulation efficiency and odor analysis after storage are shown; Table 1 shows a comparison of the release rates of microcapsules in a simulated gastrointestinal environment. Details are as follows: Table 1 Comparison of microcapsule release rates in a simulated gastrointestinal environment Compared to the control group alone, Examples 1-3 (high-voltage electrostatic field combined with ultrasound and enzyme curing) achieved the highest (>90%) and stable encapsulation rate. This indicates that the complete coupling process can most effectively encapsulate garlic essential oil inside the wall material. Control Example 1 (no high-voltage electrostatic field combined with ultrasound and no enzyme) had the lowest encapsulation rate (75.4%), indicating that the structure formed by the traditional complex coagulation method is loose and unstable, with a large amount of core material lost during drying. Control Example 2 (with high-voltage electrostatic field combined with ultrasound and no enzyme) had a significantly higher encapsulation rate (85.3%) than Control Example 1, demonstrating that the introduction of high-voltage electrostatic field combined with ultrasound can greatly optimize the structural compactness of the nascent microcapsules, significantly improving the physical encapsulation effect even without chemical cross-linking. Control Example 3 (no high-voltage electric field combined with ultrasound and enzyme) had an encapsulation rate (80.6%) higher than Control Example 1 but lower than Control Example 2, demonstrating that enzyme cross-linking can provide a certain degree of stability, but its effect depends on the structural foundation formed in the early stage. Traditional complex coagulation results in more structural defects, limiting the efficiency of enzyme cross-linking. The encapsulation efficiency data demonstrates for the first time the synergistic effect of high-voltage electrostatic field combined with ultrasound and enzyme cross-linking. The high-voltage electrostatic field combined with ultrasound creates a superior "precursor structure," providing a more efficient cross-linking platform for the enzyme, which then completely solidifies the structure. Together, they maximize the encapsulation efficiency. The analysis results of the electronic nose on the odor of the microcapsules after storage are highly consistent with the encapsulation efficiency, directly reflecting the barrier properties of the microcapsules. Examples 1-3 showed the lowest response values ​​for all sensors (especially S4, S16, and S18, which are sensitive to sulfides), indicating extremely low concentrations of volatile odor substances in their headspace. This means that the microcapsule wall material prepared by the coupled process is intact and dense, capable of almost completely sealing the pungent odor of garlic essential oil, achieving perfect flavor masking. The sensor response value of Control Example 1 far exceeded that of other groups (especially S16, whose response value was 3.85 times that of the Control Example), indicating structural failure and significant loss of flavor substances. The response values ​​of Control Examples 2 and 3 were between those of Examples 1 and Control Example 1. It is noteworthy that the response values ​​of Control Example 2 (with electric field but no enzyme) were generally lower than those of Control Example 3 (without electric field but with enzyme). This again demonstrates that the contribution of the high-voltage electrostatic field in constructing a physical barrier and preventing flavor loss is even superior to the effect of single enzyme cross-linking. Only by combining both (Examples) can the optimal flavor sealing effect be achieved. Electronic nose data confirmed the synergistic effect from a flavor perspective. This coupling technology not only increases the encapsulation volume but also ensures the quality of encapsulation, forming a leak-free barrier, which is crucial for the application of garlic essential oil in high-end foods. Simulated gastrointestinal release experiments revealed a deeper level of performance of the microcapsules—the controllability of release behavior. Examples 1-3 exhibited ideal intelligent release characteristics: slow release (<20%) in the gastric stage (0–120 min), effectively protecting the core material; after entering the intestinal stage, the release rate significantly accelerated, eventually resulting in complete release. This indicates that the microcapsules can achieve intestinal targeted delivery and improve bioavailability.Control Example 1 rapidly disintegrated in gastric juice, releasing nearly 60% within 30 minutes, without any sustained-release or targeted function. While Control Examples 2 and 3 partially improved burst release, their gastric release rates at 120 minutes remained as high as 60.5% and 78.5%, respectively, indicating their structures could not effectively resist the gastric environment and lacked targeting capabilities. The release data functionally demonstrates the value of the synergistic effect. The high-voltage electrostatic field combined with ultrasound constructed a dense primary structure, providing excellent physical barrier properties; enzyme cross-linking endowed the structure with strong chemical stability, resisting gastric juice erosion. Together, they created an intelligent delivery system capable of responding to environmental changes (pH, enzymes) and achieving "gastric protection-intestinal release." The high-voltage electrostatic field's role is "meticulous construction," precisely guiding oppositely charged wall materials to orientedly encapsulate oil droplets, forming a dense, defect-free, and uniform "pre-fabricated shell." Enzyme cross-linking's role is "permanent reinforcement," covalently bonding and reinforcing the high-quality "pre-fabricated shell" constructed by the electric field, enabling it to withstand the harsh conditions of drying, storage, and the gastrointestinal environment. No single technology can achieve the triple superior performance of high encapsulation rate, ultimate flavor masking, and intelligent targeted release that can be achieved through the synergy of these two technologies. The garlic essential oil microcapsules prepared by the process of this invention are not only a simple encapsulation method, but also an advanced delivery system that can achieve functionally targeted design, with extremely high application value.

Claims

1. A method for preparing controllably released garlic essential oil microcapsules using a high-voltage electrostatic field-ultrasound assisted process, characterized in that, The main steps include: (1) Preparation of wall material solution: Dissolve whey protein isolate in deionized water, stir and hydrate to obtain whey protein isolate solution; Gum arabic is dissolved in deionized water and stirred to obtain a gum arabic solution; the two solutions, namely the isolated whey protein and the gum arabic solution, are mixed evenly to form an isolated whey protein-gum arabic composite wall material solution; (2) Preparation of emulsion: Garlic essential oil and the isolated whey protein-gum arabic composite wall material solution prepared in step (1) are mixed according to a fixed core material and wall material mass ratio, and primary emulsification is carried out using a high-speed shear machine, followed by fine emulsification using a high-pressure homogenizer to obtain a stable O / W type emulsion. (3) High voltage electrostatic field combined with ultrasound-assisted coagulation: The pH value of the O / W type emulsion obtained in step (2) was adjusted to 4.0 with 1% hydrochloric acid solution to induce coagulation of isolated whey protein and gum arabic; this coagulated solution was placed in a high voltage electrostatic field combined with ultrasound reaction device and reacted under a specific electric field and ultrasound intensity, so that the positively charged isolated whey protein and the negatively charged gum arabic moved in a direction, cross-linked and encapsulated garlic essential oil under the drive of electric field force, forming a more regular microcapsule product; (4) Curing and cross-linking: Add transglutaminase to the aqueous solution of the microcapsule product obtained in step (3) for enzymatic cross-linking, while slowly cooling to 4 ℃ and completing curing in 12 h to strengthen the capsule wall structure. (5) Washing and drying: The solidified microcapsules are washed with 10-30% ethanol and spray-dried to obtain the dried garlic essential oil controlled release microcapsule product.

2. The method for preparing controllable release garlic essential oil microcapsules with high-voltage electrostatic field-ultrasound assistance according to claim 1, characterized in that, In step (1), the mass ratio of whey protein to gum arabic is 4:1 to 4:2, and the total concentration of the composite wall material is 1% to 3% (w / v).

3. The method for preparing controllable release garlic essential oil microcapsules with high-voltage electrostatic field-ultrasound assistance according to claim 1, characterized in that, In step (2), the core-wall mass ratio, i.e., the ratio of whey protein-gum arabic composite wall material to garlic essential oil, is 4:1 to 2:1; the high-speed shearing conditions are 1000 to 2000 rpm for 2 to 5 min; the high-pressure homogenization conditions are 30 to 50 MPa, and the high-pressure homogenization cycle is 2 to 3 times.

4. The method for preparing controllable release garlic essential oil microcapsules with high-voltage electrostatic field-ultrasound assistance according to claim 1, characterized in that, The intensity range of the high voltage electrostatic field in step (3) is 10~25 kV / cm, the processing time is 20~60 min, and the processing temperature is 40~50 ℃.

5. The method for preparing controllable release garlic essential oil microcapsules with high-voltage electrostatic field-ultrasound assistance according to claim 1, characterized in that, The power range of the ultrasound in step (3) is 40~80 W, and the processing time is 20~60 min.

6. The method for preparing controllable release garlic essential oil microcapsules with high-voltage electrostatic field-ultrasound assistance according to claim 1, characterized in that, In step (4), the amount of transglutaminase added is 20~40 U / g protein, the cross-linking temperature is 45~50 ℃, and the time is 1~2 h.

7. The method for preparing controllable release garlic essential oil microcapsules with high-voltage electrostatic field-ultrasound assistance according to claim 1, characterized in that, Step (5) The inlet temperature of the spray dryer is 120-160 ℃, the outlet temperature is 70-100 ℃, and the flow rate is 12-18 mL / min.

8. The garlic essential oil microcapsules prepared by the method according to any one of claims 1 to 7, characterized in that, The microcapsules have an encapsulation rate of no less than 90% and exhibit intelligent release characteristics of gastric sustained release and intestinal targeted release in a simulated gastrointestinal environment.

9. The garlic essential oil microcapsules prepared according to claim 8, characterized in that... In a simulated gastrointestinal environment, the gastric sustained-release rate was <20% after 2 hours; the intestinal targeted release rate was >70% after the following 2 hours.

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