A method for preparing bacteriostatic controlled-release microcapsules embedding high-volatility alpha, beta-unsaturated aldehydes

Abstract

This invention belongs to the field of food preservation and microcapsule preparation technology. By optimizing the enzymatic hydrolysis process of soybean protein hydrolysate as the wall material, it solves the technical problems of α,β-unsaturated aldehydes, such as volatility, poor stability, low encapsulation rate, and easy loss of performance. Specifically, this invention relates to a method for preparing microcapsules using enzymatically hydrolyzed soybean protein and maltodextrin as a composite wall material to encapsulate α,β-unsaturated aldehydes. The method first optimizes the preparation process of soybean protein hydrolysate, then mixes it with maltodextrin to prepare a wall material solution. After adding α,β-unsaturated aldehydes, the solution is homogenized under high pressure to refine the core material particles, promoting the adsorption of the wall material to form an interfacial film, thus preparing a stable pre-emulsion. Finally, the solution is spray-dried to obtain microcapsule powder. This invention, by optimizing the enzymatic hydrolysis conditions of soybean protein, can significantly improve the encapsulation rate of microcapsules, enhance the stability of α,β-unsaturated aldehydes, and effectively maintain their performance. It is suitable for the cold storage and preservation of chilled meat, extending shelf life.

Description

Technical Field

[0001] This invention belongs to the field of green food preservation technology, specifically relating to a method for preparing antibacterial controlled-release microcapsules encapsulating highly volatile α,β-unsaturated aldehydes. Background Technology

[0002] α,β-Unsaturated aldehydes (such as cinnamaldehyde, perillaldehyde, citral, styracil, bergamotaldehyde, and neraldehyde) possess significant antibacterial and antioxidant activities, making them valuable natural additives for food preservation. However, these compounds exhibit high volatility and are extremely sensitive to external environmental factors such as light, heat, and oxygen, making them highly susceptible to oxidative degradation or volatilization loss during conventional food processing and storage.

[0003] Microencapsulation technology, as an effective encapsulation method, encapsulates active substances within microscale structures by constructing wall material systems of specific materials. This technology effectively isolates active substances from direct erosion by adverse environmental factors such as oxygen, light, and pH fluctuations, thereby significantly improving the stability of active substances, reducing their loss during processing and storage, and enabling the controlled release of active ingredients under specific conditions. However, while traditional single natural soybean protein possesses a certain film-forming ability, its large relative molecular mass and dense spherical spatial folded structure result in poor molecular flexibility, severely burying abundant hydrophobic groups within. After moderate enzymatic hydrolysis of soybean protein to form hydrolysates, its peptide chain structure breaks down, significantly reducing its molecular weight. This not only increases molecular flexibility but also fully exposes the hydrophobic amino acid residues within the molecule, greatly enhancing surface hydrophobicity and oil-water interface adsorption capacity, making it easier to form a stable emulsion layer. Soybean protein hydrolysates, when used alone as a wall material, suffer from poor film continuity and insufficient mechanical strength, making it difficult to independently form a robust and non-porous physical barrier. When combined with maltodextrin, which has excellent film-forming properties, the two intertwine in the network structure and complement each other through hydrophobic interactions, thus jointly constructing a dense and coherent composite wall material network, thereby significantly enhancing the dispersion and encapsulation capabilities of the microcapsule system for the hydrophobic core material.

[0004] The binding of soybean protein hydrolysate to α,β-unsaturated aldehydes exhibits significant uniqueness, primarily manifested in the synergistic effect of covalent and non-covalent interactions, and closely regulated by the structure of the soybean protein hydrolysate and reaction conditions. Covalent binding is the core mechanism, where α,β-unsaturated aldehydes can bind their aldehyde groups to specific groups in soybean protein hydrolysate to form Schiff base compounds, thereby establishing stable covalent bonds. Non-covalent interactions, mainly hydrophobic interactions, play a supporting role in binding. The short peptides generated from enzymatic hydrolysis of soybean protein expose a large number of hydrophobic amino acid residues. These residues bind to the hydrophobic chains of α,β-unsaturated aldehydes through hydrophobic interactions and hydrogen bonds, thereby reducing the volatility of the aldehydes. The structural characteristics of soybean protein hydrolysate determine its superior binding capacity compared to whole soybean protein, as it reduces steric hindrance, exposes more binding sites, and its flexible conformation can adapt to the molecular structure of aldehydes, further enhancing binding efficiency. Furthermore, the binding effect is significantly affected by reaction conditions: higher oxidation levels weaken hydrophobic interactions but enhance covalent interactions; suitable temperature and pH promote the exposure of binding sites and increase the reactivity of nucleophilic groups, thereby optimizing the binding effect of the two substances.

[0005] Currently, there are reports on the application of soybean protein hydrolysates as encapsulation carriers. CN121445094A discloses a microcapsule composition with sustained-release function, its preparation method, and its application. This composition utilizes a composite gel network formed by three-stage hydrolyzed soybean protein and maltodextrin for physical isolation and targeted sustained release of probiotics. Additionally, CN112273654A discloses a method for preparing soybean protein hydrolysate aggregates using a pH-driven method to encapsulate curcumin nanoparticles. This method successfully achieves efficient loading of non-volatile plant polyphenols (curcumin) using this nanoparticle carrier. However, most of these existing technologies focus on the encapsulation and protection of live microorganisms (such as probiotics) or non-volatile solid active ingredients (such as polyphenols). Compared to non-volatile components, volatile active substances are extremely prone to leakage and loss during processing and encapsulation. Achieving efficient encapsulation and long-term physical preservation is technically very difficult. Currently, there are few reports on using soybean protein hydrolysate and maltodextrin as a composite wall material to encapsulate volatile active substances. Summary of the Invention

[0006] To address the gaps in existing technologies, this patent proposes a novel microencapsulation strategy, specifically targeting α,β-unsaturated aldehydes, which possess strong hydrophobicity and are highly volatile, and contain conjugated carbon chains and aromatic ring structures. This invention utilizes a composite system of moderately enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin. Through the strong hydrophobic interaction between the hydrophobic regions of the wall material and the α,β-unsaturated aldehydes, efficient encapsulation of volatile core materials is achieved. This system significantly overcomes the problems of volatile component loss and leakage in complex systems. The prepared microcapsules not only improve the water dispersibility and structural stability of these active substances but also extend their sustained-release period under complex storage conditions. In food applications (especially in meat product preservation), the soybean protein-based microcapsules provided by this invention effectively protect the antibacterial and antioxidant activities of the core material, demonstrating high practical value in improving food sensory quality, extending shelf life, and enhancing system stability.

[0007] This invention first provides a method for preparing antibacterial microcapsules for encapsulating highly volatile α,β-unsaturated aldehyde active substances. By optimizing the enzymatic hydrolysis process of soybean protein, a high-performance soybean protein hydrolysate / maltodextrin composite wall material system is constructed. Its encapsulation performance and structural characteristics during microcapsule formation are systematically analyzed, thereby improving the stability and overall performance of the protein-based microcapsules. Secondly, this invention provides a method for food preservation based on the above-mentioned microcapsules. The prepared antibacterial microcapsules are applied to a refrigerated pork system to exert their slow-release antibacterial and antioxidant effects, thereby maintaining the freshness of the pork and extending its shelf life.

[0008] This invention is achieved through the following technical solution: A method for preparing antibacterial control microcapsules encapsulating highly volatile α,β-unsaturated aldehydes includes the following steps: (1) Preparation of soy protein isolate aqueous solution: Soy protein isolate is dissolved in deionized water and magnetically stirred to form soy protein isolate aqueous solution; (2) Preparation of protease solution: Dissolve the protease in deionized water, shake, and prepare a protease solution; (3) Preparation of enzymatically hydrolyzed soybean protein: The protease solution and soybean protein isolate solution were mixed (50~60℃, pH=7~8) and partially enzymatically hydrolyzed (enzymatic hydrolysis time is 100~140 min), and then freeze-dried into powder. (4) Preparation of enzymatic hydrolysate of soybean protein / maltodextrin solution: The obtained enzymatic hydrolysate of soybean protein powder and maltodextrin (glucose equivalent: 10.0~15.0) were dissolved in deionized water at a ratio of 1:1 and fully hydrated to form an enzymatic hydrolysate of soybean protein / maltodextrin wall solution. (5) Preparation of emulsion based on enzymatically hydrolyzed soybean protein / maltodextrin: The active substance is added to the wall solution of enzymatically hydrolyzed soybean protein / maltodextrin, sheared, and homogenized under high pressure to prepare the emulsion; (6) Microcapsules based on enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin composite wall material were prepared by spray drying.

[0009] Microcapsules were applied to the processing of refrigerated pork tenderloin: pork tenderloin was cut into groups, and microcapsules were placed in non-woven gauze bags next to the pork tenderloin samples. All samples were placed in plastic petri dishes, sealed with plastic wrap, and stored at 4°C. The entire operation was carried out under aseptic conditions.

[0010] Further, the specific operation of step (1) is as follows: a certain amount of soy protein isolate (5% w / v) is weighed and dispersed in deionized water, and stirred with a magnetic stirrer for 2 h at room temperature to make it fully hydrated.

[0011] Further, the specific operation of step (2) is as follows: according to the appropriate protease to substrate mass ratio (1~1.5% E / S), weigh a certain amount of protease and dissolve it in deionized water, shake for 2~3 min until completely dissolved.

[0012] Further, the specific operation of step (4) is as follows: a certain amount of enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin are mixed in deionized water to prepare a wall solution. The solution is stirred continuously for 2 hours with a magnetic stirrer to completely dissolve it, and then left overnight in a refrigerator at 4°C to fully hydrate it.

[0013] Further, the specific operation of step (5) is as follows: a constant temperature water bath is heated to 25°C using a heat-collecting constant temperature magnetic stirrer and continuously stirred. Active substances are added dropwise and stirred for 1 hour. The emulsion is continuously homogenized at 10,000 r / min for 5 minutes using a high-speed shear mill to obtain an aqueous emulsion. The emulsion is then passed through a high-pressure homogenizer at 30-50 MPa for 2-3 cycles to achieve secondary emulsification.

[0014] Further, the specific operation of step (6) is as follows: First, the prepared emulsion is processed into microcapsule powder using a spray dryer. The inlet air temperature of the spray dryer is set to 170~190℃, the feed pump is set to 35%, and the outlet temperature is set to 85~105℃. The emulsion is pumped into the atomization system at a stable flow rate. After high-speed atomization, it comes into full contact with hot air, and the moisture evaporates rapidly to obtain dry microcapsule powder. The obtained powder is collected, sealed, and stored at low temperature and away from light, thus completing the preparation of microcapsules.

[0015] The beneficial effects of this invention are reflected in: (1) In this invention, enzymatically hydrolyzed soybean protein is used as one of the wall material components of the microcapsules. The surface of the protein molecules is rich in a large number of amino active groups, which undergo a specific Schiff base reaction with α,β-unsaturated aldehydes to form a stable covalent cross-linked structure. This reaction can enhance the density of the wall material network, firmly bind the volatile active core material, reduce the volatilization and leakage of substances, and thus significantly improve the encapsulation efficiency of the microcapsules.

[0016] (2) In this invention, enzymatically hydrolyzed soybean protein is used as one of the wall material components of the microcapsules. After enzymatic hydrolysis, the peptide bonds within the protein molecules are broken down by the enzyme, resulting in smaller peptide chains and an increase in the number of effective binding sites. Enzymatic hydrolysis promotes the breakdown of peptide chains, thereby exposing the hydrophobic amino acid residues inside the protein, increasing the hydrophobicity of the protein surface and its affinity for lipophilic bioactive compounds. At the same time, enzymatic hydrolysis can further reduce the oil-water interfacial tension and improve the emulsifying performance of the enzymatically hydrolyzed protein system.

[0017] (3) All experimental raw materials used in this invention are green and pollution-free natural materials, among which the active ingredients are known for their strong antibacterial properties and edibility. Soy protein isolate is not only abundant, but also has excellent emulsification and gelling properties. As a plant-based protein, it has advantages such as biocompatibility, biodegradability, high availability, non-toxicity, low cost and long-term stability, making it an ideal wall material for microencapsulation technology.

[0018] (4) This invention uses a composite of maltodextrin and enzymatically hydrolyzed soybean protein as the wall material. Maltodextrin is a starch hydrolysis product and is commonly used for microencapsulation of food ingredients. The addition of polysaccharides helps to form a secondary protective layer on the primary protein layer, thereby enhancing the steric hindrance effect of the repulsive force between droplets. At the same time, it has advantages such as good solubility, neutral odor and flavor, low viscosity at high concentrations, and ideal antioxidant stability for the core material. The protein and polysaccharide form a complex, preparing microcapsules with enhanced stability and optimized structural properties.

[0019] (5) The proteoglycan microcapsules prepared by this invention exhibit a normal particle size distribution and have uniform and concentrated dispersion characteristics. The concentrated particle size distribution and significant polydispersity make them an ideal material for achieving stable encapsulation of core materials and controlled-release systems. This size reduction can improve the absorption rate and bioavailability of microcapsules, especially in systems requiring rapid release or controlled release.

[0020] (6) The microcapsules prepared by spray drying in this invention encapsulate the active substances into the shell of the microcapsules, which on the one hand plays a protective role, and on the other hand has low cost, industrialization convenience, cost-effectiveness, high yield and high output, compatibility with a variety of coating materials, and can handle heat-sensitive materials due to the short drying time.

[0021] (7) The microcapsules prepared by this invention have good controlled-release effect. The sustained release behavior can be divided into two stages: the first stage involves rapid evaporation from the surface of the microcapsule, and the second stage is sustained release from the inside of the microcapsule to the outside. Microencapsulation encapsulates the active substance in a protective matrix, effectively protecting it from external factors and achieving controlled release. This characteristic enhances their applicability in food preservation, where the sustained-release active substance can effectively play a role in food preservation and quality protection.

[0022] (8) The enzymatically hydrolyzed soybean protein / maltodextrin / cinnamaldehyde microcapsules prepared in this invention have good antibacterial activity and can release cinnamaldehyde in a controlled manner to inhibit the growth of Escherichia coli and Staphylococcus aureus. Cinnamaldehyde can interfere with the activity of key metabolic enzymes of microorganisms, causing protein denaturation and altering cell wall permeability, thereby achieving an antibacterial effect.

[0023] (9) The microcapsules prepared by the present invention can preserve the freshness of refrigerated pork through sustained release, and can maintain the appearance, pH value, texture characteristics and oxidation degree of pork tenderloin for a longer period of time, thereby extending the shelf life of fresh pork tenderloin. Attached Figure Description

[0024] Figure 1 The changes in degree of hydrolysis and DPPH free radical scavenging rate of soybean protein hydrolysate under different enzymatic hydrolysis times; Figure 2 The microcapsule encapsulation rates for each embodiment and comparative example; Figure 3 The inhibition zone of enzymatically hydrolyzed soybean protein / maltodextrin / cinnamaldehyde microcapsules against Escherichia coli; Figure 4 The inhibition zone of enzymatically hydrolyzed soybean protein / maltodextrin / cinnamaldehyde microcapsules against Staphylococcus aureus; Figure 5 The appearance changes of chilled pork tenderloin under the treatment of soy protein / maltodextrin / cinnamaldehyde microcapsules, enzymatic hydrolysis of soy protein / maltodextrin / cinnamaldehyde microcapsules at different hydrolysis times, and blank control group. Figure 6 Scanning electron microscope image of the enzymatically hydrolyzed soybean protein / maltodextrin / cinnamaldehyde microcapsules prepared in Example 1. Detailed Implementation

[0025] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result of the description. However, the embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0026] Maltodextrin was purchased from Qinhuangdao Lihua Starch Co., Ltd., CAS No.: 9050-36-6, Item No.: 01170016, with a glucose equivalent of 10.0-12.0 (Examples 1-6, Comparative Examples 1-10, 14-15). Maltodextrin was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., CAS No.: 9050-36-6, Item No.: 767484, with a glucose equivalent of 13.0-17.0 (Comparative Example 11). Maltodextrin was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., CAS No.: 9050-36-6, product number: 768506, with a glucose equivalent of 16.5-19.5 (comparative example 12). Cyclodextrin was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., CAS No.: 7585-39-9, item number: C804562 (Comparative Example 13).

[0027] Example 1 The preparation steps of cinnamaldehyde microcapsules using soybean protein hydrolysates with different degrees of enzymatic hydrolysis as wall materials are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Cinnamaldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / cinnamaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / cinnamaldehyde were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0028] Comparative Example 1 The preparation steps of cinnamaldehyde microcapsules using soybean protein as the wall material are as follows: (1) Soy protein and maltodextrin are dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to obtain a soy protein / maltodextrin wall solution; (2) Cinnamaldehyde was added to the wall solution at a wall-to-core mass ratio of 3:2. The mixture was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare a soybean protein / maltodextrin / cinnamaldehyde emulsion. Soybean protein / maltodextrin / cinnamaldehyde microcapsules were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0029] Comparative Example 2 The preparation steps of cinnamaldehyde microcapsules using soybean protein hydrolysates with different degrees of enzymatic hydrolysis as wall materials are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 90 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Cinnamaldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / cinnamaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / cinnamaldehyde were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0030] Comparative Example 3 The preparation steps of cinnamaldehyde microcapsules using soybean protein hydrolysates with different degrees of enzymatic hydrolysis as wall materials are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer for 2 h at room temperature to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 150 min. Freeze-dry to obtain powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Cinnamaldehyde was added to the wall solution at a wall-to-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / cinnamaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / cinnamaldehyde were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0031] Example 1 of effect verification The enzymatic hydrolysis process of soybean protein hydrolysate was analyzed (determination of degree of hydrolysis and DPPH free radical scavenging rate). (1) Determination of degree of hydrolysis: The soybean protein hydrolysate was diluted with deionized water to 2 g / L. 3.81 g disodium tetraborate and 0.1 g sodium dodecyl sulfate were dispersed in 80 mL of deionized water, and o-phthalalaldehyde (OPA, 160 mg dissolved in 4 mL of ethanol) and dithiothreitol (176 mg dissolved in 1 mL of deionized water) were added to make up to 100 mL to prepare OPA reagent.

[0032] Add 200 μL of the hydrolysate to 1.5 mL of OPA reagent, mix well, and react for 2 min. Measure the absorbance at 340 nm and record it as OD. sample Mix 200 μL of serine standard solution (0.1 mg / ml) with 1.5 ml of OPA for 5 seconds, and record the OD value as OD. standard .

[0033] In the formula, h tot = 7.8 (mmol / g protein); α = 0.970; β = 0.342; X Sample mass (g); P The percentage of protein in the sample is %.

[0034] (2) Determination of DPPH free radical scavenging rate: 4 mL of DPPH reagent (0.1 mmol / L, dissolved in 95% methanol solution) was mixed with 1 mL of soybean protein hydrolysate solution (1 mg / mL), and reacted for 30 min under light-protected conditions. The absorbance was read at 517 nm using an ELISA reader. Glutathione was used as a positive control.

[0035] The DPPH radical scavenging capacity is calculated using the following formula: In the formula, A blank The absorbance of the solution containing no sample is given. A sample The absorbance of the sample to be tested; A control This represents the absorbance of the sample solution itself.

[0036] Table 1. Changes in degree of hydrolysis and DPPH free radical scavenging rate of soybean protein hydrolysate at different enzymatic hydrolysis times. From Table 1 and Figure 1 It can be seen that the degree of hydrolysis of soybean protein hydrolysate steadily increases with increasing enzymatic hydrolysis time, while the DPPH free radical scavenging rate reaches its highest level (23.43±0.98%) at an enzymatic hydrolysis time of 120 min. This demonstrates that soybean protein hydrolysate exhibits the strongest antioxidant properties within an enzymatic hydrolysis time of 100–140 min.

[0037] Among the cinnamaldehyde microcapsules prepared from the enzymatic hydrolysate of soybean protein / maltodextrin composite wall material, the microcapsules prepared from the soybean protein hydrolysate treated with 120 min of enzymatic hydrolysis showed the highest encapsulation rate of cinnamaldehyde, reaching 68.93±1.56%.

[0038] Example 2 Perillaldehyde microcapsules were prepared using soybean protein hydrolysate prepared with papain as the wall material. Kiwi protease, papain, and fig protease are all plant-derived, cysteine-type endopeptidases, and their activity depends on sulfhydryl groups. The steps are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh an appropriate amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min. Freeze-dry to obtain powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Perillaldehyde was added to the wall solution at a mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / perillaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / perillaldehyde were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0039] Comparative Example 4 The preparation steps of perillaldehyde microcapsules using soybean protein hydrolysate prepared with alkaline protease as the wall material are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh an appropriate amount of alkaline protease and dissolve it in deionized water. Shake for 2 min. Mix the alkaline protease solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min. Freeze-dry to obtain powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Perillaldehyde was added to the wall solution at a mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / perillaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / perillaldehyde were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0040] Comparative Example 5 Perillaldehyde microcapsules were prepared using soybean protein hydrolysate prepared with trypsin as the wall material. The steps are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of trypsin and dissolve it in deionized water. Shake for 2 min. Mix the trypsin solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min. Freeze-dry to obtain powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Perillaldehyde was added to the wall solution at a mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / perillaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / perillaldehyde were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0041] Comparative Example 6 Perillaldehyde microcapsules were prepared using soybean protein hydrolysate obtained through a three-step enzymatic hydrolysis process as the wall material. The steps are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir it with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Perform proteolytic hydrolysis in three stages: In the first stage, add 0.5g of alkaline protease, the hydrolysis pH is 10.0, the hydrolysis temperature is 55℃, and the hydrolysis time is 60 min; In the second stage, add 0.5g of alkaline protease and 0.5g of bromelain, the hydrolysis pH is 7.0, the hydrolysis temperature is 55℃, and the hydrolysis time is 60 min; In the third stage, add 0.3g of carboxypeptidase B, the hydrolysis pH is 8.5, the hydrolysis temperature is 50℃, and the hydrolysis time is 60 min. After hydrolysis, perform high-temperature enzyme inactivation, cool, and freeze-dry to obtain powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Perillaldehyde was added to the wall solution at a mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / perillaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / perillaldehyde were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0042] Example 3 The preparation steps of citral microcapsules using soybean protein hydrolysates under different enzymatic hydrolysis conditions as wall materials are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Citral was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / citral emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / citral were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0043] Comparative Example 7 The preparation steps of citral microcapsules using soybean protein hydrolysates under different enzymatic hydrolysis conditions as wall materials are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (40℃, pH=6.0) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Citral was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / citral emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / citral were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0044] Comparative Example 8 The preparation steps of citral microcapsules using soybean protein hydrolysates under different enzymatic hydrolysis conditions as wall materials are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to fully hydrate it. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (70℃, pH=9.0) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Citral was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / citral emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / citral were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0045] Example 4 The following steps were taken to prepare quinallanth microcapsules using soybean protein hydrolysates with different enzyme-substrate ratios as wall materials: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Green leaf aldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / green leaf aldehyde emulsion. Enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / green leaf aldehyde microcapsules were prepared by spray drying. The spray drying process parameters were: inlet air temperature 180℃, feed pump 35%, outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0046] Comparative Example 9 The following steps were taken to prepare quinallanth microcapsules using soybean protein hydrolysates with different enzyme-substrate ratios as wall materials: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.65% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Green leaf aldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / green leaf aldehyde emulsion. Enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / green leaf aldehyde microcapsules were prepared by spray drying. The spray drying process parameters were: inlet air temperature 180℃, feed pump 35%, outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0047] Comparative Example 10 The following steps were taken to prepare quinallanth microcapsules using soybean protein hydrolysates with different enzyme-substrate ratios as wall materials: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (0.90% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Green leaf aldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / green leaf aldehyde emulsion. Enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / green leaf aldehyde microcapsules were prepared by spray drying. The spray drying process parameters were: inlet air temperature 180℃, feed pump 35%, outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0048] Example 5 The steps for preparing bergamot aldehyde microcapsules using different types of dextrin and soybean protein hydrolysate as composite wall materials are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Bergamotaldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / bergamotaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / bergamotaldehyde were prepared by spray drying. The spray drying process parameters were: inlet air temperature 180℃, feed pump 35%, outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0049] Comparative Example 11 The steps for preparing bergamot aldehyde microcapsules using different types of dextrin and soybean protein hydrolysate as composite wall materials are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:2 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Bergamotaldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / bergamotaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / bergamotaldehyde were prepared by spray drying. The spray drying process parameters were: inlet air temperature 180℃, feed pump 35%, outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0050] Comparative Example 12 The steps for preparing bergamot aldehyde microcapsules using different types of dextrin and soybean protein hydrolysate as composite wall materials are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 2:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Bergamotaldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / bergamotaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / bergamotaldehyde were prepared by spray drying. The spray drying process parameters were: air inlet temperature 180℃, feed pump 35%, and outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0051] Comparative Example 13 The steps for preparing bergamot aldehyde microcapsules using different types of dextrin and soybean protein hydrolysate as composite wall materials are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (55℃, pH=7.5) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and cyclodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Bergamotaldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / bergamotaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / bergamotaldehyde were prepared by spray drying. The spray drying process parameters were: inlet air temperature 180℃, feed pump 35%, outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0052] Example 6 Neraldehyde microcapsules were prepared using soybean protein hydrolysates obtained at different high-pressure homogenization pressures and spray drying temperatures as wall materials. The steps are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (50℃, pH=7.0) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Neraldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / neraldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / neraldehyde were prepared by spray drying. The spray drying process parameters were: inlet air temperature 180℃, feed pump 35%, outlet temperature 95℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0053] Comparative Example 14 Neraldehyde microcapsules were prepared using soybean protein hydrolysates obtained at different high-pressure homogenization pressures and spray drying temperatures as wall materials. The steps are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (50℃, pH=7.0) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Neraldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 20 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / neraldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / neraldehyde were prepared by spray drying. The spray drying process parameters were: inlet air temperature 160℃, feed pump 35%, outlet temperature 85℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0054] Comparative Example 15 Neraldehyde microcapsules were prepared using soybean protein hydrolysates obtained at different high-pressure homogenization pressures and spray drying temperatures as wall materials. The steps are as follows: (1) Weigh a certain amount of soy protein isolate (5% w / v) and disperse it in deionized water. Stir with a magnetic stirrer at room temperature for 2 h to ensure complete hydration. Weigh a certain amount of papain and dissolve it in deionized water. Shake for 2 min. Mix the papain solution with the soy protein isolate solution at a suitable protease to substrate mass ratio (1.25% E / S). Enzymatically hydrolyze the mixture under specific conditions (50℃, pH=7.0) for 120 min and freeze-dry it into powder. (2) The enzymatically hydrolyzed soybean protein hydrolysate and maltodextrin were dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Neraldehyde was added to the wall solution at a wall-core mass ratio of 3:2. The solution was sheared and homogenized under high pressure of 60 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / neraldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / neraldehyde were prepared by spray drying. The spray drying process parameters were: inlet air temperature 200℃, feed pump 35%, outlet temperature 105℃. The dried powder was sealed in a sealed bag and stored at 4℃.

[0055] Example 2 of effect verification Determination of microcapsule encapsulation efficiency: First, standard curves for each active substance were established. A full-wavelength scan was performed on α,β-unsaturated aldehydes using anhydrous ethanol as the solvent to determine the maximum absorption wavelength required for measurement. At the maximum absorption wavelength, a standard curve of concentration versus absorbance was established for aldehyde samples using anhydrous ethanol as the solvent. Simultaneously, 100 mg of microcapsules were weighed and added to 10 ml of anhydrous ethanol, mixed well, and centrifuged at 8000 r / min for 15 min. The supernatant was used to measure the content of α,β-unsaturated aldehydes on the microcapsule surface. Alternatively, 100 mg of microcapsules were added to 10 ml of anhydrous ethanol, sonicated for 1 h, and the solution was centrifuged. The resulting supernatant was used to determine the total content of α,β-unsaturated aldehydes. The percentage of α,β-unsaturated aldehydes encapsulated in the microcapsules (EE) was calculated as follows: In the formula, C 1 It refers to the content of α,β-unsaturated aldehydes on the surface of the microcapsules. C 2 It represents the total content of active α,β-unsaturated aldehydes.

[0056] Table 2 Microcapsule encapsulation efficiency of the examples and comparative examples According to Table 2 and Figure 2It is known that under enzymatic hydrolysis conditions of 40-60℃, pH 6-8, and enzyme-substrate ratio of 0.1-0.3%, soybean protein was hydrolyzed using at least one of the following proteases: bromelain, papain, and figase. The resulting soybean protein hydrolysate was then combined with maltodextrin (glucose equivalent: 10.0-12.0) at a mass ratio of 1:1 to serve as the microcapsule wall material. After homogenization under high pressure of 30-50 MPa, microcapsules were prepared under spray drying conditions with an inlet temperature of 170-190℃ and an outlet temperature of 85-105℃. These microcapsules exhibited high encapsulation efficiency for various α,β-unsaturated aldehydes (such as cinnamaldehyde, perillaldehyde, citral, styraxaldehyde, bergamotaldehyde, and neraldehyde).

[0057] Example 7 Antibacterial experiments were conducted on the microcapsules with antibacterial and food preservation properties of Example 1 and its comparative examples. The specific operating steps were as follows: (1) Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus After activation in liquid culture medium, the strain was inoculated onto Luria-Bertani agar plates for subculture, and the culture was repeated 2-3 times. (2) Use an inoculation needle to pick up a single colony on the plate and inoculate it into the liquid culture medium, and place it in a shaker at 37°C overnight until the mid-log phase of the bacterial culture; (3) Prepare 6 mm diameter holes on an agar plate and fill them with enzymatically hydrolyzed and unhydrolyzed soybean protein microcapsule powder; (4) Take 100 μL of solution with a concentration of 10 8 CFU / mL bacterial suspension was evenly spread on agar plates, and the plates were inverted and incubated at 37°C for 24 h. The inhibition zones were observed and recorded.

[0058] Example 3 of effect verification The antibacterial activity of the microcapsules was quantitatively evaluated by measuring the diameter (mm) of the inhibition zone on each plate. Figure 2 , Figure 3 It is evident that the obtained microcapsule powder exhibits good inhibitory effects against both Escherichia coli and Staphylococcus aureus.

[0059] Table 3 As shown in Table 3, Figure 3 , Figure 4The inhibition zones formed by the microcapsules loaded with cinnamaldehyde against *Escherichia coli* and *Staphylococcus aureus* had diameters of 25.13 ± 4.13 mm and 30.33 ± 2.12 mm, respectively. Since both diameters exceeded 25 mm, it can be concluded that the microcapsules prepared from the hydrolysate of soybean protein obtained under enzymatic hydrolysis conditions of 100–140 min possess significant antibacterial activity. This activity is mainly attributed to cinnamaldehyde interfering with the activity of key enzymes involved in energy metabolism, leading to protein denaturation and altered microbial cell wall permeability. The antibacterial activity of cinnamaldehyde against *Staphylococcus aureus* was stronger than that against *Escherichia coli*. This difference stems from the fact that Gram-positive bacteria lack an outer membrane, while the outer membrane of Gram-negative bacteria is composed of substances such as lipopolysaccharides.

[0060] Example 8 A food preservative for meat preservation, comparing the preservation effects of enzymatically hydrolyzed and unenzymatically hydrolyzed soybean protein microcapsules prepared according to Example 1 and its comparative examples.

[0061] The microcapsules with antibacterial and food preservation properties of this embodiment were used in a cold-refrigerated pork tenderloin preservation experiment. The specific operation steps are as follows: (1) The enzymatically hydrolyzed soybean protein hydrolysate (enzymatic hydrolysis time is 0, 90, 120, 150 min) and maltodextrin are dissolved in deionized water at a mass ratio of 1:1 and fully hydrated to form an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin wall solution. Cinnamaldehyde is added to the wall solution at a wall-to-core ratio of 3:2. The solution is sheared and homogenized under high pressure of 40 MPa for 2-3 cycles to prepare an enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / cinnamaldehyde emulsion. Microcapsules of enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / cinnamaldehyde are prepared by spray drying. The spray drying process parameters are: air inlet temperature 180℃, feed pump 35%, outlet temperature 95℃. The dried powder is sealed in a sealed bag and stored at 4℃. (2) Fresh pork tenderloin within 12 hours after slaughter is used, and the temperature is maintained within the range of 0~4℃ during transportation; (3) Sample preparation followed the Chinese national standard GB / T 9695.19-2008. Under aseptic conditions, pork tenderloin was cut and grouped. (4) The microcapsules were put into non-woven gauze bags and placed next to the pork tenderloin samples. All samples were placed in plastic petri dishes and stored at 4°C with the petri dishes sealed with plastic wrap. (5) The entire operation was performed under aseptic conditions. All instruments were disinfected with 75% ethanol and irradiated with ultraviolet light for 20 min before use. Samples were taken for analysis on storage days 0, 2, 4, 6, 8, 10, 12 and 14. A blank control group (empty nonwoven bag) and a positive control group (equal concentration of free cinnamaldehyde) were set up.

[0062] Example 4 of effect verification A study on the preservation effects of un-enzymatically hydrolyzed and enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin / cinnamaldehyde microcapsules on pork, such as... Figure 5 As shown.

[0063] The color of refrigerated pork is a key indicator of its freshness, and the spoilage process involves complex physicochemical reactions. Microbial proliferation and enzymatic reactions lead to muscle protein degradation, decreased water retention capacity, and cell sap leakage, which in turn causes nutrient decomposition, pigment destruction, and off-flavor formation. All experimental groups of meat samples maintained relatively stable color during the first four days of refrigerated storage, while the control group showed significant quality deterioration, specifically marked by significant moisture loss, a color change from bright red to dark reddish-brown, and decreased surface gloss. After the sixth day of storage, the deterioration characteristics of the control group were more pronounced, showing obvious darkening and surface shrinkage. Comparative analysis results showed that the color deterioration of the soybean protein / maltodextrin microcapsule treatment group was delayed by about two days compared to the control group, demonstrating a moderate protective effect of the wall material on pork tenderloin. Among them, microcapsules prepared from soybean protein hydrolysate with an enzymatic hydrolysis time of 100–140 min showed the best preservation effect on refrigerated pork tenderloin.

[0064] Although the present invention has been described in detail with reference to preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the invention should also be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be determined by the scope of the claims.

Claims

1. A process for the preparation of bacteriostatic controlled release microcapsules embedding a high volatile α,β-unsaturated aldehyde, characterized in that, Includes the following steps: (1) Preparation of soy protein isolate aqueous solution: Soy protein isolate is dissolved in deionized water and magnetically stirred to form soy protein isolate aqueous solution; (2) Preparation of protease solution: Dissolve the protease in deionized water, shake, and prepare a protease solution; (3) Preparation of enzymatically hydrolyzed soybean protein hydrolysate: The protease solution and soybean protein isolate solution are mixed, and after partial enzymatic hydrolysis, the mixture is freeze-dried into powder; (4) Preparation of enzymatic hydrolysate of soybean protein / maltodextrin solution: Dissolve the obtained enzymatic hydrolysate of soybean protein powder and maltodextrin in deionized water and fully hydrate to form an enzymatic hydrolysate of soybean protein / maltodextrin wall solution. (5) Preparation of emulsion based on enzymatically hydrolyzed soybean protein / maltodextrin: The active substance is added to the wall solution of enzymatically hydrolyzed soybean protein / maltodextrin, sheared, and homogenized under high pressure to prepare the emulsion; (6) Microcapsules based on enzymatically hydrolyzed soybean protein hydrolysate / maltodextrin composite wall material were prepared by spray drying.

2. The process for the preparation of the bacteriostatic controlled release microcapsules embedding high volatile α,β-unsaturated aldehydes according to claim 1, characterized by the fact that: The enzymatic hydrolysis time is 100~140 min.

3. The method for preparing antibacterial controlled-release microcapsules encapsulating highly volatile α,β-unsaturated aldehydes according to claim 1, characterized in that: The enzymatic hydrolysis conditions are a temperature of 50-60℃ and a pH of 7-8.

4. The method for preparing antibacterial controlled-release microcapsules encapsulating highly volatile α,β-unsaturated aldehydes according to claim 1, characterized in that: The protease is at least one of papain, kiwifruit protease, and fig protease.

5. The method for preparing antibacterial controlled-release microcapsules encapsulating highly volatile α,β-unsaturated aldehydes according to claim 1, characterized in that: The ratio of the protease to the substrate is 1 to 1.5%.

6. The method of preparing the bacteriostatic controlled release microcapsule embedding a high volatility α,β-unsaturated aldehyde according to claim 1, characterized by: The active substance is an α,β-unsaturated aldehyde, preferably one of cinnamaldehyde, perillaldehyde, citral, styraxaldehyde, bergamotaldehyde, and neraldehyde.

7. The method of producing bacteria-inhibiting controlled-release microcapsules embedding a high-volatility α,β-unsaturated aldehyde according to claim 1, characterized by: The mass ratio of the enzymatically hydrolyzed soybean protein hydrolysate to dextrin is 1:1, wherein the glucose equivalent of the maltodextrin is 10.0-12.

0.

8. The method of producing bacteria-inhibiting controlled-release microcapsules embedding a high-volatility α,β-unsaturated aldehyde according to claim 1, characterized by: The high-pressure homogenization pressure is 30~50 MPa.

9. The method of producing bacteria-inhibiting controlled-release microcapsules embedding a high-volatility α,β-unsaturated aldehyde according to claim 1, characterized by: The inlet temperature of the spray drying operation is 170~190℃, and the outlet temperature is 85~105℃.

10. The microcapsules prepared by the preparation method according to any one of claims 1-9 are used in a food preservative for meat preservation.

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