A wasabi essential oil microcapsule and a method for preparing the same

Abstract

The application discloses a wasabi essential oil microcapsule and a preparation method thereof, and belongs to the field of essential oil extraction. The wasabi essential oil microcapsule takes wasabi essential oil extracted by supercritical CO2 as core material, takes sodium alginate solution and gelatin solution as wall material, and selects chitosan oligosaccharide calcium complex to solidify the microcapsule, so that the stability of the obtained wasabi essential oil microcapsule is improved. The preparation method of the wasabi essential oil microcapsule comprises the following steps: mixing wasabi essential oil, sodium alginate solution and gelatin solution, and then performing emulsification treatment, so that the embedding rate of the microcapsule is enhanced; and then performing defoaming treatment, so that the loss of effective components caused after emulsification is prevented, the preparation method can effectively reduce the loss of the wasabi essential oil microcapsule caused in the preparation process, and the stability of the prepared wasabi essential oil microcapsule is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of plant essential oil, and particularly relates to a wasabi essential oil microcapsule and a preparation method thereof. BACKGROUND

[0002] Wasabi is an aromatic plant that can exhibit strong taste and fresh pleasant aroma, and can be used as a high-end essential oil in the food, beauty and pharmaceutical industries. However, its actual application effect is low. On the one hand, it is volatile essential oil, which has defects such as unstable composition and easy volatilization. On the other hand, the pungent flavor of wasabi essential oil is mainly from characteristic flavor substance isothiocyanate (ITCs), and ITCs are water-soluble and prone to degradation by nucleophilic addition reaction, resulting in a decrease in the characteristic flavor of the essential oil.

[0003] In view of the above problems, CN103876242A (Patent name: A microcapsule against food-borne pathogenic bacteria and a preparation method and use thereof) discloses a microcapsule with distilled and extracted wasabi essential oil and olive oil as core material, natural edible gum as wall material, and the essential oil is wrapped by changing pH value and temperature and other conditions to make gelatin and gum arabic complex coacervation, so as to reduce the release rate of wasabi essential oil during use and storage. However, in the technical solution, the water bath emulsification coacervation at 45℃ and the solidification process for 4-6h under alkaline conditions cause serious degradation of ITCs, which further leads to a decrease in the pungent flavor of wasabi essential oil. SUMMARY

[0004] Based on the above problems, the present application provides a wasabi essential oil microcapsule, which uses wasabi essential oil extracted by supercritical CO2 as core material, sodium alginate solution and gelatin solution as wall material, and selects chitosan calcium complex to solidify the microcapsule, so that the stability of the obtained wasabi essential oil microcapsule is improved. The present application also provides a preparation method of wasabi essential oil microcapsule, which mixes wasabi essential oil with sodium alginate solution and gelatin solution, then performs emulsification treatment to enhance the embedding rate of the microcapsule, and then performs defoaming treatment to prevent possible loss of active ingredients after emulsification, so that the preparation method can effectively reduce the loss of wasabi essential oil microcapsule during preparation, and at the same time improve the stability of the prepared wasabi essential oil microcapsule.

[0005] Based on the above problems, the first technical means of the present application discloses a wasabi essential oil microcapsule, which comprises

[0006] Core material: wasabi essential oil;

[0007] Wall material: sodium alginate solution and gelatin solution; and

[0008] Chitosan calcium complex.

[0009] Further, the wasabi essential oil is obtained by supercritical CO2 extraction of pretreated wasabi root hairs.

[0010] Further, the chitosan oligosaccharide calcium complex is obtained by dissolving chitosan oligosaccharide in a calcium chloride solution.

[0011] Preferably, the concentration of the calcium chloride solution is 0.012-0.018 g / mL, and the addition amount of the chitosan oligosaccharide is 0.01%-0.02% of the calcium chloride solution.

[0012] Preferably, the addition amounts of the wasabi essential oil, the sodium alginate solution, the gelatin solution and the chitosan oligosaccharide calcium complex are 1: (4-6): (4-6): (0.2-0.5).

[0013] The second technical solution of the present application discloses a preparation method of wasabi essential oil microcapsules, comprising:

[0014] The wasabi essential oil core material is obtained by supercritical CO2 extraction of pretreated wasabi root hairs.

[0015] The wasabi essential oil core material, the sodium alginate solution and the gelatin solution are mixed to obtain an emulsion through emulsification treatment.

[0016] The emulsion and the chitosan oligosaccharide calcium complex are mixed to obtain a microcapsule crude product through gelation.

[0017] The microcapsule crude product is filtered, washed and freeze-dried to obtain a wasabi essential oil microcapsule finished product.

[0018] Preferably, the emulsification treatment condition is 10000-12000 rpm for 2-3 min.

[0019] Further, the emulsification treatment further comprises defoaming treatment, and the defoaming treatment is performed by using a self-rotating low-temperature vacuum stirring defoaming machine, and the stirring condition is controlled to be 2-5 min of defoaming under a vacuum pressure of 133 Pa.

[0020] Preferably, the gelation time is 50-60 min.

[0021] Further, the wasabi essential oil microcapsule is prepared according to the preparation method.

[0022] The wasabi essential oil microcapsule has the following advantages:

[0023] The present application aims at the problem that the prior art Zanthoxylum bungeanum essential oil microcapsule needs to add an emulsifier for emulsification and then add a wall material for embedding, which leads to a low embedding rate, and selects sodium alginate solution and gelatin solution as the wall material, which can play the roles of emulsification and embedding, and when the sodium alginate solution and the gelatin solution are compounded, the sodium alginate can improve the mechanical properties of the gelatin, and the gelatin can improve the spheroidization of the sodium alginate, thereby enhancing the mechanical strength of the microcapsule and the embedding rate of the Zanthoxylum bungeanum essential oil; then, calcium chitosan oligosaccharide complex is added to crosslink with the sodium alginate, so that the stability of the effective component of the product obtained is enhanced compared with the prior art.

[0024] The present application aims at the problem that in the prior art preparation method of Zanthoxylum bungeanum essential oil microcapsule, emulsification is generally carried out at about 45 DEG C, which leads to serious degradation of ITCs, and the sodium alginate solution and the gelatin solution are used as the emulsifier and the wall material, and then a high-speed emulsification method and a defoaming treatment method after emulsification are combined to prepare the Zanthoxylum bungeanum essential oil microcapsule; compared with the prior art, the preparation method can effectively reduce the loss rate of ITCs in the preparation process, and the stability of the effective component of the Zanthoxylum bungeanum essential oil microcapsule prepared is enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The test results of the retention rate of the Zanthoxylum bungeanum essential oil microcapsule prepared in Examples 1-3 and Comparative Examples 1-6 during storage. DETAILED DESCRIPTION

[0026] The following examples are used to specifically describe the present application, and it is necessary to point out that the following examples are only used to further illustrate the present application and cannot be understood as a limitation on the protection scope of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application according to the content of the present application.

[0027] In the prior art, an emulsifier is generally added before embedding the essential oil to emulsify it, but this method leads to a low embedding rate of the essential oil, so most of the current researches turn to selecting a microcapsule wall material that has both emulsification and embedding functions, such as sodium alginate, gelatin, gum arabic, milk protein, etc., but the above wall materials are mostly single, and the single wall material faces many defects.

[0028] Therefore, the first embodiment of the present application discloses a Zanthoxylum bungeanum essential oil microcapsule, which comprises a core material: Zanthoxylum bungeanum essential oil; a wall material: sodium alginate solution and gelatin solution; and calcium chitosan oligosaccharide complex.

[0029] It should be noted that the wasabi essential oil described in this application is obtained by supercritical CO2 extraction of pretreated wasabi roots. Because the characteristic flavor compounds (ITCs) of wasabi are water-soluble, traditional distillation extraction methods using water as a medium result in significant ITC loss, high oil loss, and low yield. Furthermore, extraction with organic solvents leaves solvent residues, making it difficult to effectively obtain finished wasabi essential oil. Supercritical CO2 extraction is a technique that involves contacting a supercritical CO2 fluid with the substance to be separated under supercritical conditions, selectively extracting components based on polarity, boiling point, and molecular weight. Using supercritical CO2 extraction to extract wasabi essential oil prevents the reduction of water-soluble ITCs, maximizes the retention of aroma and flavor components, and leaves no solvent residue. The pretreated wasabi roots are prepared by crushing wasabi roots with a water content of less than 10% and passing them through a 40-mesh sieve.

[0030] In some specific embodiments, the parameters of the supercritical CO2 extraction can be generally adjusted by those skilled in the art based on the properties of the raw materials and the required extraction rate. In some preferred embodiments, the supercritical extraction conditions are: particle size 40 mesh, extraction time 90 min, extraction vessel temperature 45°C, extraction vessel pressure 30 MPa, separation vessel temperature 45°C, and separation vessel pressure 10 MPa.

[0031] It should be noted that the mixture of sodium alginate solution and gel solution described in this application serves as both an emulsifying core material for essential oils and a wall material for microcapsules. When used alone, sodium alginate has strong hydrophilicity, resulting in large pore sizes in the gel, which leads to a rapid release rate of essential oils and a tendency for burst release. Gelatin, on the other hand, suffers from brittle gels and poor mechanical properties. By combining the two materials, sodium alginate can improve the mechanical properties of gelatin, and gelatin can improve the spherical shape of sodium alginate, thereby enhancing the mechanical strength of the microcapsules and the encapsulation rate of wasabi essential oil, and improving the stability of the essential oil.

[0032] It should be noted that the chitosan oligosaccharide calcium complex described in this application is obtained by dissolving chitosan oligosaccharide in calcium chloride solution, which plays a role in solidifying microcapsules and improving their stability. Currently, when using sodium alginate as a microcapsule wall material, there are methods that use calcium chloride solution as a curing agent to mix with sodium alginate to stabilize the outer wall of the microcapsules. However, when sodium alginate and calcium chloride solution are mixed, due to the Ca... 2+ It will rapidly undergo ionic complexation with the α-1,4-d-guluronic acid units in sodium alginate, forming a cross-linked structure. Once the cross-linked structure is formed, Ca... 2+ It becomes difficult for the α-1,4-d-guluronic acid units contained within the cross-linked structure to diffuse into the Ca2+ structure, making it difficult for them to bind with Ca2+. 2+The reaction occurs, therefore, this kind of diplomatic connection technique often causes the local overcrosslinking of sodium alginate on the surface of microcapsule, the overall local crosslinking degree is too low, thereby causing the uneven embedding, influence microcapsule in the storage process stability. In order to solve the above problems, the present application first dissolves chitosan oligosaccharide in calcium chloride solution to obtain chitosan oligosaccharide calcium complex, then adds it to the microcapsule solution, and the chitosan oligosaccharide calcium complex can control Ca 2+ And the crosslinking speed of sodium alginate, ensure the reaction of internal crosslinking structure, make the reaction uniform, more conducive to the stability of microcapsule.

[0033] In some specific embodiments, the concentration of calcium chloride solution, the amount of chitosan added, and the ratio of core material to wall material are all obtained by general adjustment by those skilled in the art according to the yield and properties of microcapsule; in some preferred embodiments, the concentration of calcium chloride solution is 0.012-0.018 g / mL, the amount of chitosan oligosaccharide added is 0.01%-0.02% of the calcium chloride solution, and in some preferred embodiments, the amount of wasabi essential oil: sodium alginate solution: gelatin solution: chitosan oligosaccharide calcium complex is 1: (4-6): (4-6): (0.2-0.5).

[0034] The second embodiment of the present application discloses a preparation method of wasabi essential oil microcapsule, comprising: supercritical CO2 extraction pretreatment wasabi root hair to obtain wasabi essential oil core material; mixing wasabi essential oil core material, sodium alginate solution, gelatin solution, and emulsifying to obtain emulsion; mixing emulsion and chitosan oligosaccharide calcium complex, and gelling to obtain microcapsule crude product; filtering, washing, and freeze-drying the microcapsule crude product to obtain wasabi essential oil microcapsule finished product.

[0035] It should be noted that the emulsifier of the emulsification treatment is sodium alginate solution and gelatin solution, and the above solutions are also used as the wall material of the microcapsule; thereby avoiding the problem of reduced embedding rate caused by using other emulsifiers for emulsification and then using other wall materials for embedding in the prior art.

[0036] It should be noted that the emulsification treatment conditions can be obtained by general adjustment by those skilled in the art according to the embedding rate and loss rate; in some preferred embodiments, the emulsification treatment conditions are to control the rotation speed to 10000-12000 rpm for 2-3 min, and the purpose of controlling the emulsification conditions is to accelerate the emulsification rate of essential oil. In the prior art, after adding essential oil core material into sodium alginate and gelatin solution, it is usually necessary to stir at a constant temperature of 45℃ or above for a long time to make the essential oil emulsify completely, and this process for preparing wasabi essential oil microcapsule will cause the spicy flavor of wasabi essential oil to decrease significantly, because the characteristic flavor substance ITCs in wasabi essential oil has water solubility and as the temperature rises, the two π bonds of ITCs become active, the hydrolysis rate of ITCs accelerates, and when the temperature rises to 65℃, the hydrolysis rate accelerates significantly.

[0037] The applicant found that since both sodium alginate and gelatin have strong emulsifying properties, the addition of wasabi essential oil into a mixed solution of sodium alginate and gelatin and stirring at 10,000-12,000 rpm for 2-3 min can make the wasabi essential oil completely emulsified and stable within 50-60 min. Compared with the prior art, this emulsification condition can achieve the technical effect of uniformly dispersing the sodium alginate solution and the gelatin solution at room temperature (20-30°C) to promote sufficient emulsification, while effectively shortening the emulsification time, ensuring the stability of the emulsion during the formation of microcapsules and retaining the content of ITCs in the essential oil. However, since this technical means mainly relies on high-speed stirring to achieve emulsification, the high speed can cause the raw materials to heat up and generate a large amount of protein foam, which makes the emulsion remain at a high temperature for a long time during subsequent processing, resulting in continuous loss of effective components in the wasabi essential oil. At the same time, a large amount of foam causes pores between the emulsion droplets, and the structure is not tight, which affects the embedding effect of the capsules and reduces the embedding rate of the essential oil. Therefore, under this emulsification condition, defoaming treatment needs to be performed immediately after emulsification to quickly reduce the temperature raised by high-speed emulsification, avoiding the problems of loss of effective components in the essential oil and reduction of the microcapsule embedding rate. The defoaming treatment is performed using a self-rotating low-temperature vacuum stirring defoaming machine, and the stirring conditions are controlled to be a vacuum pressure of 130-140 Pa and defoaming for 2-5 min.

[0038] In some specific embodiments, the gelation is the process of solidifying the preliminarily emulsified and embedded emulsion by the chitosan oligosaccharide calcium complex, and in this process, the chitosan oligosaccharide calcium complex crosslinks with the sodium alginate of the emulsion, which is beneficial to the stability of the wasabi essential oil microcapsules. The gelation time can be obtained by general experiments according to the stability test of the wasabi essential oil microcapsules by those skilled in the art, and in some preferred embodiments, the gelation time is 50-60 min.

[0039] In some specific embodiments, the method for filtering, washing and freeze-drying the microcapsule crude product to obtain the wasabi essential oil microcapsule product can be selected by those skilled in the art according to specific experimental conditions, and will not be described herein; in some preferred embodiments, the microcapsule crude product needs to be frozen at -20°C for 8-10 h before freeze-drying after washing; in some preferred embodiments, the freeze-drying conditions are: temperature -50°C, pressure 1.1 Pa, and time 22-24 h.

[0040] The following specific examples and corresponding comparative examples will be disclosed to demonstrate the technical effects of the present application.

[0041] Example 1 Preparation of wasabi essential oil microcapsules

[0042] 1. Preparation of core material: The water content of the wasabi root is less than 10%, which is crushed and passed through a 40-mesh sieve. The extraction time is controlled at 90 min, the extraction kettle temperature is 45℃, the extraction kettle pressure is 30 MPa, the separation kettle 1 temperature is 45℃, and the separation kettle 1 pressure is 10 MPa. Supercritical CO2 extraction is carried out to obtain wasabi essential oil core material;

[0043] 2. Preparation of chitosan oligosaccharide calcium complex: 0.01% mass fraction of chitosan oligosaccharide is dissolved in 0.015 g / mg of calcium chloride solution to obtain chitosan oligosaccharide calcium complex;

[0044] 3. Preparation of wasabi essential oil microcapsule:

[0045] (1) 10 kg of wasabi essential oil core material, 50 kg of sodium alginate solution and 50 kg of gelatin solution are mixed, and a high-speed stirrer is used at 11000 rmp for 2 min to obtain an emulsion;

[0046] (2) The emulsion is placed in a self-rotating low-temperature vacuum stirring defoaming machine, and defoaming treatment is carried out at a vacuum pressure of 133 Pa for 3 min to obtain a defoaming emulsion;

[0047] (3) 0.3 kg of chitosan oligosaccharide calcium complex is added to the defoaming emulsion, and gelling is carried out for 55 min to obtain a crude product of microcapsules;

[0048] (4) The crude product of microcapsules is filtered out, washed with distilled water, frozen at-20℃ for 9h, and then freeze-dried at a temperature of-50℃ and a pressure of 1.1 Pa for 23h to obtain a finished product of wasabi essential oil microcapsules.

[0049] Example 2 Preparation of wasabi essential oil microcapsules

[0050] 1. Preparation of core material: The water content of the wasabi root is less than 10%, which is crushed and passed through a 40-mesh sieve. The extraction time is controlled at 90 min, the extraction kettle temperature is 45℃, the extraction kettle pressure is 30 MPa, the separation kettle 1 temperature is 45℃, and the separation kettle 1 pressure is 10 MPa. Supercritical CO2 extraction is carried out to obtain wasabi essential oil core material;

[0051] 2. Preparation of chitosan oligosaccharide calcium complex: 0.02% mass fraction of chitosan oligosaccharide is dissolved in 0.012 g / mg of calcium chloride solution to obtain chitosan oligosaccharide calcium complex;

[0052] 3. Preparation of wasabi essential oil microcapsule:

[0053] (1) 10 kg of wasabi essential oil core material, 40 kg of sodium alginate solution and 40 kg of gelatin solution are mixed, and a high-speed stirrer is used at 11000 rmp for 2 min to obtain an emulsion;

[0054] (2) The emulsion is placed in a self-rotating low-temperature vacuum stirring defoaming machine, and defoaming treatment is carried out under a vacuum pressure of 130 Pa for 2 min to obtain a defoamed emulsion;

[0055] (3) 0.2 kg of chitosan oligosaccharide calcium complex is added to the defoamed emulsion, and gelling is carried out for 50 min to obtain a crude microcapsule product;

[0056] (4) The crude microcapsule product is filtered out, washed with distilled water, frozen at-20°C for 8 h, and then freeze-dried under the conditions of a temperature of-50°C and a pressure of 1.1 Pa for 22 h to obtain a finished product of the wasabi essential oil microcapsule.

[0057] Example 3: Preparation of a wasabi essential oil microcapsule

[0058] 1. Preparation of a core material: wasabi root and stem powder with a water content of less than 10% is crushed through a 40-mesh sieve, and supercritical CO2 extraction is carried out under the following conditions: an extraction time of 90 min, an extraction kettle temperature of 45°C, an extraction kettle pressure of 30 MPa, a separation kettle temperature of 45°C, and a separation kettle pressure of 10 MPa to obtain a wasabi essential oil core material;

[0059] 2. Preparation of a chitosan oligosaccharide calcium complex: 0.02% by mass of chitosan oligosaccharide is dissolved in a 0.018 g / mg calcium chloride solution to obtain a chitosan oligosaccharide calcium complex;

[0060] 3. Preparation of a wasabi essential oil microcapsule:

[0061] (1) 10 kg of the wasabi essential oil core material, 60 kg of a sodium alginate solution, and 60 kg of a gelatin solution are mixed, and a high-speed stirrer is used to treat the mixture under the conditions of 12000 rmp for 3 min to obtain an emulsion;

[0062] (2) The emulsion is placed in a self-rotating low-temperature vacuum stirring defoaming machine, and defoaming treatment is carried out under a vacuum pressure of 140 Pa for 5 min to obtain a defoamed emulsion;

[0063] (3) 0.5 kg of the chitosan oligosaccharide calcium complex is added to the defoamed emulsion, and gelling is carried out for 60 min to obtain a crude microcapsule product;

[0064] (4) The crude microcapsule product is filtered out, washed with distilled water, frozen at-20°C for 10 h, and then freeze-dried under the conditions of a temperature of-50°C and a pressure of 1.1 Pa for 24 h to obtain a finished product of the wasabi essential oil microcapsule.

[0065] Comparative Example 1: Preparation of a wasabi essential oil microcapsule

[0066] The preparation method is the same as that of Example 1, except that distillation extraction technology is used instead of supercritical CO2 extraction technology to prepare the wasabi essential oil.

[0067] Comparative Example 2: Preparation of a wasabi essential oil microcapsule

[0068] The preparation method is the same as example 1, except that the emulsification process of comparative example 2 is stirring for 50 min in a constant temperature water bath at 45°C.

[0069] Comparative example 3: Preparation of wasabi essential oil microcapsules

[0070] The preparation method is the same as example 1, except that comparative example 3 is not defoaming treatment.

[0071] Comparative example 4: Preparation of wasabi essential oil microcapsules

[0072] The preparation method is the same as example 1, except that comparative example 4 does not add gelatin.

[0073] Comparative example 5: Preparation of wasabi essential oil microcapsules

[0074] The preparation method is the same as example 1, except that comparative example 5 does not add sodium alginate.

[0075] Comparative example 6: Preparation of wasabi essential oil microcapsules

[0076] The preparation method is the same as example 1, except that comparative example 6 replaces chitosan oligosaccharide calcium complex with calcium chloride.

[0077] Test example 1: Detection of ITCs content of wasabi essential oil microcapsules

[0078] The flavor substance of wasabi is ITCs produced by the hydrolysis of sulfur glucoside in plant tissues by endogenous myrosinase, and the content is an important indicator for measuring the quality of wasabi products. The quality of wasabi essential oil microcapsules can be analyzed by detecting the content of ITCs.

[0079] ITCs detection method: accurately weigh 0.1 g of wasabi essential oil microcapsules prepared in examples 1-3 and comparative examples 1-7, and place them in a 50 mL round-bottom flask. Add 25 mL of n-hexane, and stir magnetically at 25°C for 2 h, then ultrasonically treat at room temperature for 10 min. Then, heat the mixture in a water bath at 60°C for 15 min, and place it at 4°C overnight until complete phase separation. The isothiocyanate content is determined by the direct titration method with hexacyanopyridine.

[0080] Experimental results: see table 1.

[0081] Result analysis: From Table 1, the ITCs of Examples 1-3 are all between 75%-80%, which shows that the microcapsules of wasabi essential oil prepared by the process of the application have high content of characteristic substances ITCs and strong spicy flavor. The ITCs content of Example 1 is significantly higher than that of Comparative Example 1, which shows that the distillation extraction technology with water as the medium causes serious loss of ITCs in wasabi essential oil, and the supercritical CO2 extraction technology can effectively retain the ITCs in wasabi, and obtain wasabi essential oil with strong flavor. Compared with Comparative Example 2, the ITCs content of Comparative Example 4 is less than 45%, which shows that with the increase of temperature, the two π bonds of ITCs become active, the hydrolysis of ITCs is accelerated, and the loss is increased, so the ITCs content of the prepared wasabi essential oil microcapsules is low, and the flavor is seriously decreased. Compared with Comparative Example 3, the ITCs content of Example 1 is higher than that of Comparative Example 3, which is because the rotation speed is too fast during the emulsification process, and the raw material is heated, which causes the effective components ITCs to be lost in the subsequent processing process under high temperature environment, so the ITCs content of the prepared wasabi essential oil is reduced, and the flavor is decreased. Compared with Comparative Examples 4-6, the ITCs content of Example 1 has little difference, which is because the selection of microcapsule wall material and solidification solution mainly affects the stability of wasabi essential oil microcapsules, and has little effect on the content of characteristic substances ITCs.

[0082] Table 1 ITCs content test results

[0083] .

[0084] Test Example 2: Release test of wasabi essential oil microcapsules during storage

[0085] The retention rate of wasabi essential oil microcapsules was evaluated by the content of main component ITCs of wasabi essential oil, and the stability of wasabi essential oil microcapsules during storage was analyzed. The retention rate of wasabi essential oil without microcapsule treatment (hereinafter referred to as untreated essential oil) was measured by direct weighing method. The wasabi essential oil microcapsules and untreated essential oil were stored at 25°C, and the retention rate was tested every 7d, and the storage time was 35d. The retention rate calculation formula of wasabi essential oil microcapsules is as follows:

[0086] ;

[0087] In the formula: m A -ITCs content of microcapsules after storage;

[0088] m B -ITCs content of microcapsules before storage.

[0089] The experimental results are shown in Figure 1 : The microcapsule and essential oil retention rate test results of wasabi essential oil microcapsules prepared by Examples 1-3 and Comparative Examples 1-6 during storage.

[0090] The results show that the retention rates of the wasabi essential oil microcapsules of Examples 1-3 are all above 90 after 35 days of storage, indicating that the microcapsules prepared by the process of the application exhibit good slow controlled release performance and good stability during storage. The retention rates of Examples, Comparative Examples and untreated essential oil are all higher than that of untreated essential oil, indicating that the microcapsule technology can protect the wasabi essential oil from the environment and reduce and control the release rate of the essential oil by embedding the wasabi essential oil. The essential oil retention rates of Example 1 and Comparative Examples 1-3 are not much different, because the extraction, emulsification and defoaming process of wasabi essential oil mainly affects the content of characteristic substance ITCs and has little effect on the stability of wasabi essential oil microcapsules. The retention rates of Comparative Examples 4 and 5 are significantly decreased compared with Example 1 and Comparative Example 5, and the slow controlled release performance of the microcapsules is poor, because sodium alginate has strong hydrophilicity, the microcapsules prepared in Comparative Example 4 have large pore size, and the brittleness and mechanical properties of gelatin are poor, and the wall material of the microcapsules prepared in Comparative Example 5 is prone to change during storage, such as dehydration and brittleness or moisture absorption and humidity, thereby leading to a decrease in stability and a fast release rate of the essential oil. This indicates that the combination of sodium alginate and gelatin as the wall material plays a role in improving the mechanical properties of gelatin, and gelatin improves the spheroidization of sodium alginate, thereby enhancing the mechanical strength of the wasabi essential oil microcapsules and controlling the slow release rate of the essential oil. The retention rate of Example 1 is slightly higher than that of Comparative Example 6, indicating that dissolving chitosan oligosaccharide in calcium chloride solution to obtain chitosan oligosaccharide calcium complex and then adding it to the microcapsule solution can improve the stability of the microcapsules, because only using calcium chloride solution as a solidifying agent to mix with sodium alginate to stabilize the stability of the outer wall of the microcapsules can cause local over-crosslinking of sodium alginate on the surface of the microcapsules and too low overall crosslinking degree, thereby causing uneven embedding and affecting the stability of the microcapsules during storage. The chitosan oligosaccharide calcium complex can control the crosslinking speed of Ca 2+ and sodium alginate, ensure the reaction of the internal crosslinking structure, make the reaction uniform, and thereby ensure the high stability of the microcapsules.

[0091] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the application, but not to limit them; although the application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A method for preparing microcapsules of wasabi essential oil, characterized by, The method comprises the following steps: extracting the roots and rhizomes of the wasabi with supercritical CO2 to obtain a wasabi essential oil core material; mixing the wasabi essential oil core material, a sodium alginate solution and a gelatin solution, and performing emulsification treatment to obtain an emulsion; mixing the emulsion and a chitosan oligosaccharide calcium complex, and performing gelation to obtain a crude product of the microcapsule; filtering, washing and freeze-drying the crude product of the microcapsule to obtain a finished product of the wasabi essential oil microcapsule. The emulsification treatment is performed at a rotation speed of 10,000-12,000 rpm for 2-3 min. The emulsification treatment is further followed by defoaming treatment, which is performed by using a self-rotating low-temperature vacuum stirring defoaming machine, and the stirring conditions are controlled as follows: a vacuum pressure of 130-140 Pa and defoaming for 2-5 min.

2. The production method according to claim 1, characterized by, The chitosan oligosaccharide calcium complex is obtained by dissolving chitosan oligosaccharide in a calcium chloride solution.

3. The production method according to claim 2, characterized by, The concentration of the calcium chloride solution is 0.012-0.018 g / mL, and the addition amount of the chitosan oligosaccharide is 0.01%-0.02% of the calcium chloride solution.

4. The production method according to claim 1, characterized by, The addition amounts of the wasabi essential oil, the sodium alginate solution, the gelatin solution and the chitosan oligosaccharide calcium complex are 1: (4-6): (4-6): (0.2-0.5).

5. The method of claim 1, wherein, The gelation time is 50-60 min.

6. A wasabi essential oil microcapsule prepared by the method according to any one of claims 1-5.

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