A plant essential oil microcapsule and its preparation method and application

Abstract

The present invention discloses a plant essential oil microcapsule, a preparation method, and an application thereof. The invention belongs to the field of plant essential oil technology. The invention explores the preparation of plant essential oil (CEO) microcapsules by encapsulating AITC into the cavity of CD, using it together with polysaccharides such as gum arabic, pectin, and carrageenan, or proteinaceous materials such as gelatin as wall materials, and single or composite plant essential oils such as eugenol, cuminaldehyde, and thymol as core materials. Compared with the prior art, the present invention achieves the following beneficial effects: (1) the raw materials used in the preparation are all natural substances and are safe and harmless to the human body; and (2) it is conducive to storage and application.

Description

Technical Field

[0001] The present invention relates to the technical field of plant essential oils, and more particularly to a plant essential oil microcapsule and a preparation method and application thereof. Background Art

[0002] Essential oils (EOs) not only serve as natural preservatives but are also environmentally friendly. Different essential oils exhibit varying antibacterial and antioxidant properties. For example, allyl isothiocyanate (AITC), a potent active ingredient in cruciferous vegetables such as rapeseed and cabbage, is a broad-spectrum antibacterial agent that inhibits not only bacterial growth but also fungal activity. Eugenol not only exhibits strong inhibitory effects against bacteria and fungi but also exhibits excellent antioxidant activity, making it suitable for meat preservation. Thyme oil isolated from the herb thyme (the primary active ingredient is thymol) exhibits strong antibacterial activity and can be used as an alternative to synthetic fungicides. Various scientific investigations of cumin seeds and cumin oil (the primary active ingredient is cuminaldehyde) have demonstrated numerous biological activities, including antibacterial, antifungal, and antioxidant activities.

[0003] Because essential oils are mostly derived from aromatic plants, they possess a distinctive odor and high volatility. Studies have shown that encapsulating them can improve their physical and chemical properties, such as solubility and volatility, thereby inhibiting the release of the core material and prolonging its duration of action. Therefore, essential oil microencapsulation continues to attract researchers' attention as an environmentally friendly and alternative method for improving the quality of meat products.

[0004] Spray drying is a long-established method for preparing microcapsules and remains the most widely used in the food industry due to its low production cost and optimal encapsulation efficiency. The choice of wall material is crucial for spray-drying microcapsule preparation. Gum arabic, maltodextrin, and cyclodextrin are commonly used as microcapsule wall materials, and their use, whether alone or in combination, can improve encapsulation efficiency. β-cyclodextrin (β-CD) was first discovered by Villers in 1891, and its structure was characterized by Frendenberg and French in 1935. It is characterized by a hydrophilic exocyclic ring, a hydrophobic intracyclic ring, and a dimensional cavity of a certain size. This cavity can encapsulate a variety of compounds to form inclusion complexes. β-CD is relatively stable and can be stored for years without deterioration. It is highly reactive due to the presence of numerous primary and secondary hydroxyl groups and other reactive groups.

[0005] Currently, the antioxidant effect of AITC microcapsules is very poor, and the microcapsules easily absorb water, causing changes in physical properties, such as agglomeration and stickiness.

[0006] In summary, how to provide a plant essential oil microcapsule with good antioxidant effect and low water absorption is a problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0007] In light of this, the present invention provides plant essential oil microcapsules, their preparation method, and applications. This invention explores the preparation of plant essential oil (CEO) microcapsules by encapsulating AITC into the cavity of CDs, combining them with polysaccharides such as gum arabic, pectin, or carrageenan, or proteins such as gelatin, as wall materials, and using single or composite plant essential oils such as eugenol, cuminaldehyde, and thymol as core materials.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A plant essential oil microcapsule comprising the following components in parts by weight: 2-3 parts of allyl isothiocyanate, 1-3 parts of eugenol, 0.5-1.5 parts of thymol, 1-3 parts of cuminaldehyde, 4-6 parts of cyclodextrin, and 8-11 parts of polysaccharide or protein substances;

[0010] The polysaccharide substance is gum arabic, pectin or carrageenan;

[0011] The protein substance is gelatin.

[0012] Beneficial effects achieved: AITC exhibited strong sustained-release properties after being embedded in CD, and volatilization should be prevented during preparation.

[0013] Furthermore, a plant essential oil microcapsule comprises the following components in parts by mass: 2.5 parts of allyl isothiocyanate, 2 parts of eugenol, 1 part of thymol, 2 parts of cuminaldehyde, 5 parts of β-cyclodextrin and 10 parts of gum arabic.

[0014] The above-mentioned method for preparing plant essential oil microcapsules comprises the following steps:

[0015] (1) Preparation of AITC / CD inclusion complex

[0016] (11) preparing a CD aqueous solution with a mass concentration of 3-5%;

[0017] (12) Add a mixture of allyl isothiocyanate and ethanol dropwise to the CD aqueous solution while stirring, and stir for 3 to 5 hours;

[0018] The volume ratio of the mixture of allyl isothiocyanate and ethanol to the CD aqueous solution is 1:1 to 1:4;

[0019] (13) Filtering the residue and drying it to obtain a dry AITC / CD inclusion compound powder;

[0020] (2) Preparation of microcapsule emulsion

[0021] (21) Prepare an AITC / CD inclusion complex and gum arabic aqueous solution with a mass concentration of 23-27%, add Tween 80, stir and dissolve, and use as the wall material solution;

[0022] The mass ratio of AITC / CD inclusion complex to gum arabic in the aqueous solution of AITC / CD inclusion complex and gum arabic was 1:1;

[0023] (22) Three plant essential oils: eugenol, thymol, and cuminaldehyde were mixed to obtain a composite essential oil;

[0024] (23) mixing the composite essential oil and the wall material solution in a volume ratio of 1:4 to 1:8 and homogenizing to obtain a microcapsule emulsion;

[0025] (3) Preparation of microcapsules

[0026] The microcapsule emulsion is spray-dried.

[0027] Furthermore, in the step (12), the rotation speed under stirring is 800-1000 rpm and the temperature is 45-55°C.

[0028] Furthermore, in step (12), the volume ratio of allyl isothiocyanate to ethanol is 1:1 to 1:4.

[0029] Furthermore, the mass ratio of eugenol, thymol and cuminaldehyde in step (22) is 2:1:2 to 3:2:3.

[0030] Furthermore, the homogenization parameters in step (23) are: 750-850 r / min for 5-7 min.

[0031] Furthermore, the spray drying parameters in step (3) are: inlet air temperature 180°C, outlet air temperature 80°C.

[0032] Application of the above-mentioned plant essential oil microcapsules in preserving pork or fresh meat of livestock and poultry.

[0033] Furthermore, it is used to reduce the TBARS value in meat, delay the increase of pH value, inhibit the color change of pork, and delay the increase of TVB-N value.

[0034] The traditional approach involves mixing multiple active ingredients and then encapsulating them in microencapsulation. However, because each microcapsule can only encapsulate a limited amount of material, and the release process requires a specific ratio, precise control of the encapsulated material and its amount is difficult. AITC's primary function among these active ingredients is antibacterial, so ensuring a sufficient amount within the microcapsule is crucial. Therefore, the inclusion complex of AITC and CD as a microcapsule wall material offers a promising solution. First, there is a one-to-one correspondence between AITC and CD, meaning that one CD molecule can encapsulate one AITC molecule. This ensures sufficient AITC in the microcapsule. Furthermore, its inclusion within the wall material does not occupy internal space, allowing for the encapsulation of more essential oils. Furthermore, from a release perspective, AITC is released from the microcapsule's outer wall, while the essential oil is released from the inside of the microcapsule, without interfering with each other and allowing each active ingredient to function more effectively. To our knowledge, composite essential oil microcapsules prepared using the AITC / CD inclusion complex as a wall material have not yet been described. Our research demonstrates excellent preservation effects. This study overcomes the limitations of AITC microcapsules in the antioxidant effect on meat and the defects of microcapsules easily absorbing water and agglomerating, providing new ideas for the application of AITC in meat preservation.

[0035] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The raw materials used in the preparation are all natural substances and are safe and harmless to the human body;

[0037] (2) It is conducive to preservation and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0039] Figure 1 It is the technical roadmap of the present invention;

[0040] Figure 2 This is the CD one-dimensional NMR spectrum in Experiment 1 of the present invention;

[0041] Figure 3 This is the one-dimensional NMR spectrum of the CD inclusion complex in Experiment 1 of the present invention;

[0042] Figure 42. The left side shows the microcapsules prepared in Example 3 of the present invention, and the left side shows the microcapsules prepared in Comparative Example 1;

[0043] Figure 5 is the TBARS value in pork in Experiment 2 of the present invention;

[0044] Figure 6 is the pH value of pork in Experiment 2 of the present invention;

[0045] Figure 7 The color change of pork in Experiment 2 of the present invention, where A is the L* value; B is the a* value; C is the b* value;

[0046] Figure 8 is the TVB-N value in pork in Experiment 2 of the present invention;

[0047] Figure 9 The EE and solubility results after changing the wall material ratio and wall-core ratio in Experiment 3 of the present invention;

[0048] Figure 10 These are the EE and solubility results after changing the wall material in Experiment 3 of the present invention. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] The reagents required for the present invention are conventional experimental reagents, purchased from commercial channels; the experimental methods not mentioned are conventional experimental methods and will not be described in detail here.

[0051] Example 1

[0052] 1. Preparation of AITC / CD inclusion complex

[0053] 3 g of CD was accurately weighed into a beaker using an electronic balance, and 100 mL of water was added. The solution was then fully dissolved in a 60 °C water bath with a magnetic stirrer (HWCL-3, China) to obtain a transparent CD aqueous solution, which was then cooled to room temperature.

[0054] The magnetic stirrer was set at a speed of 800 rpm and a temperature of 45°C. AITC and ethanol were mixed evenly in a ratio of 1:1 (volume ratio) and then slowly added dropwise to the dissolved CD aqueous solution (the volume ratio of the mixture of allyl isothiocyanate and ethanol to the CD aqueous solution was 1:1). After stirring for 3 hours, the mixture was filtered using a circulating water vacuum pump. The inclusion complex on the filter paper was placed in a vacuum drying oven, set at a temperature of 60°C, and dried for a certain period of time to obtain a dry AITC / CD inclusion complex powder.

[0055] 2. Preparation of microcapsule emulsion

[0056] A 23% mass concentration of AITC / CD inclusion complex and gum arabic aqueous solution (the mass ratio of AITC / CD inclusion complex to gum arabic is 1:1) was prepared, 0.5 g of Tween 80 was added, and the mixture was stirred and dissolved in a magnetic stirrer for use as a wall material solution.

[0057] Three plant essential oils (eugenol, thymol, and cuminaldehyde) were mixed in a ratio of 2:1:2 (mass ratio) to obtain a composite essential oil.

[0058] The composite essential oil and the prepared wall material solution (volume ratio of the two is 1:4) were homogenized for 5 min using a homogenizer (Model 3000, DREMEL, Mexico) at 750 r / min to obtain a uniform and stable microcapsule emulsion, which was then sealed with a sealing film for later use.

[0059] 3. Preparation of microcapsules

[0060] The prepared microcapsule emulsion was injected into a spray dryer (SD-BASIC, Labplant, UK). The spray dryer was set to the following experimental parameters: inlet air temperature of 180°C and outlet air temperature of 80°C. After the spray dryer temperature stabilized, the peristaltic pump was turned on and adjusted to gear 3. The homogenized microcapsule emulsion flowed into the inlet at a constant rate (pump speed 3), and spray drying began. The state of the microcapsules during spray drying was observed. After the experiment, heating was stopped, and the microcapsule powder was removed after the outlet cooled to room temperature and placed in a sealed bag for later use.

[0061] Example 2

[0062] 1. Preparation of AITC / CD inclusion complex

[0063] 5 g of CD was accurately weighed into a beaker using an electronic balance, and 300 mL of water was added. The beaker was placed in an 80 °C water bath with a magnetic stirring pot (HWCL-3, China) to fully dissolve the CD solution to obtain a transparent CD aqueous solution, which was then cooled to room temperature.

[0064] The magnetic stirrer was set at a speed of 1000 rpm and a temperature of 55°C. AITC and ethanol were evenly mixed in a ratio of 1:4 (volume ratio) and then slowly added dropwise to the dissolved CD aqueous solution (the volume ratio of the mixture of allyl isothiocyanate and ethanol to the CD aqueous solution was 1:1). After stirring for 5 hours, the mixture was filtered using a circulating water vacuum pump. The inclusion complex on the filter paper was placed in a vacuum drying oven, set at a temperature of 80°C, and dried for a certain period of time to obtain a dry AITC / CD inclusion complex powder.

[0065] 2. Preparation of microcapsule emulsion

[0066] A 27% mass concentration of AITC / CD inclusion complex and pectin aqueous solution (the mass ratio of AITC / CD inclusion complex to gum arabic is 1:1) was prepared, 1 g of Tween 80 was added, and the mixture was stirred and dissolved in a magnetic stirrer for use as a wall material solution.

[0067] The composite essential oil was obtained by mixing three plant essential oils (eugenol, thymol, and cuminaldehyde) in a ratio of 3:2:2 (mass ratio).

[0068] The composite essential oil and the prepared wall material solution (volume ratio of the two is 1:4) were homogenized for 3 min using a homogenizer (Model 3000, DREMEL, Mexico) at 850 r / min to obtain a uniform and stable microcapsule emulsion, which was then sealed with a sealing film for later use.

[0069] 3. Preparation of microcapsules

[0070] The prepared microcapsule emulsion was injected into a spray dryer (SD-BASIC, Labplant, UK). The spray dryer was set to the following experimental parameters: inlet air temperature of 180°C and outlet air temperature of 80°C. After the spray dryer temperature stabilized, the peristaltic pump was turned on and adjusted to gear 3. The homogenized microcapsule emulsion flowed into the inlet at a constant rate (pump speed 3), and spray drying began. The state of the microcapsules during spray drying was observed. After the experiment, heating was stopped, and the microcapsule powder was removed after the outlet cooled to room temperature and placed in a sealed bag for later use.

[0071] Example 3

[0072] 1. Preparation of AITC / CD inclusion complex

[0073] 4 g of CD was accurately weighed into a beaker using an electronic balance, and 100 mL of water was added. The solution was then fully dissolved in a 60 °C water bath with a magnetic stirrer (HWCL-3, China) to obtain a transparent CD aqueous solution, which was then cooled to room temperature.

[0074] The magnetic stirrer was set at a speed of 900 rpm and a temperature of 65°C. AITC and ethanol were mixed evenly in a ratio of 1:1 (volume ratio) and then slowly added dropwise to the dissolved CD aqueous solution (the volume ratio of the mixture of allyl isothiocyanate and ethanol to the CD aqueous solution was 1:4). After stirring for 4 hours, the mixture was filtered using a circulating water vacuum pump. The inclusion complex on the filter paper was placed in a vacuum drying oven, set at a temperature of 70°C, and dried for a certain period of time to obtain a dry AITC / CD inclusion complex powder.

[0075] 2. Preparation of microcapsule emulsion

[0076] A 25% mass concentration of AITC / CD inclusion complex and gelatin aqueous solution (the mass ratio of AITC / CD inclusion complex to gelatin is 1:2) was prepared, 0.7 g of Tween 80 was added, and the mixture was stirred and dissolved in a magnetic stirrer for use as a wall material solution.

[0077] The composite essential oil was obtained by mixing three plant essential oils (eugenol, thymol, and cuminaldehyde) in a ratio of 3:1:2 (mass ratio).

[0078] The composite essential oil and the prepared wall material solution (volume ratio of the two is 1:4) were homogenized for 6 min using a homogenizer (Model 3000, DREMEL, Mexico) at 800 r / min to obtain a uniform and stable microcapsule emulsion, which was then sealed with a sealing film for later use.

[0079] 3. Preparation of microcapsules

[0080] The prepared microcapsule emulsion was injected into a spray dryer (SD-BASIC, Labplant, UK). The spray dryer was set to the following experimental parameters: inlet air temperature of 180°C and outlet air temperature of 80°C. After the spray dryer temperature stabilized, the peristaltic pump was turned on and adjusted to gear 3. The homogenized microcapsule emulsion flowed into the inlet at a constant rate (pump speed 3), and spray drying began. The state of the microcapsules during spray drying was observed. After the experiment, heating was stopped, and the microcapsule powder was removed after the outlet cooled to room temperature and placed in a sealed bag for later use.

[0081] Comparative Example 1

[0082] Prepare a certain concentration of gum arabic and CD aqueous solution, add an appropriate amount of Tween 80, stir and dissolve in a magnetic stirrer, and use as the wall material solution. Calculate the amount of AITC based on a core-to-wall ratio of 0.3 (w / w). Accurately aspirate AITC with a pipette and transfer it to the wall material solution. Homogenize using a homogenizer. Seal the homogenized system with parafilm. Set the spray dryer parameters according to the experimental conditions. After the spray dryer temperature stabilizes, turn on the peristaltic pump and adjust it to gear 3. The homogenized system flows into the sample inlet at a certain rate, start spray drying, and observe the state of the microcapsules during spray drying. At the end of the experiment, stop heating, cool the sample outlet to room temperature, remove the AITC microcapsule powder, place it in a sealed bag, and store it in the refrigerator for use.

[0083] Experiment 1

[0084] After AITC was embedded in CD, one-dimensional nuclear magnetic resonance (NMR) detection was required to determine whether an inclusion complex of AITC and CD was formed. The change in chemical shift values ​​revealed that the shift value of the wide-mouth section was greater than that of the narrow-mouth section, suggesting that AITC was inserted from the wide-mouth end of the CD hydrophobic cavity.

[0085] By comparing the peak areas, it was found that the peak area ratio of CD and AITC was approximately 1:1.

[0086] Thermodynamic equations show that enthalpy change ΔH = -15.173 kJ / mol, entropy change ΔS = -16.5 J / mol. Gibbs free energy ΔG = -40.55 at 20°C, -40.97 kJ / mol at 25°C, -41.4 kJ / mol at 30°C, -41.82 kJ / mol at 35°C, and -42.25 kJ / mol at 40°C.

[0087] We attempted to analyze the driving force behind the CD-AITC interaction from an energy perspective. The results showed that the Gibbs free energy, ΔG, was less than 0, indicating that the interaction occurred spontaneously. The enthalpy change, ΔH, was less than 0, indicating that the reaction was accompanied by heat release. The entropy change, ΔS, was greater than 0, indicating that the interaction occurred without a programmed increase.

[0088] CD one-dimensional NMR spectrum Figure 2 As shown;

[0089] The one-dimensional NMR spectrum of CD inclusion complex is shown in Figure 3 shown.

[0090] Experiment 2

[0091] Compare the microcapsules prepared in Example 3 and the microcapsules prepared in Comparative Example 1.

[0092] 1. Water absorption and deterioration test (Put 0.2-0.4g microcapsules into a microcapsule sustained-release bag and seal it together with 50g pork in a plastic bag and store it in a -4℃ refrigerator)

[0093] The results are as follows Figure 4 As shown (the figure shows the 6th day).

[0094] It is clear that the microcapsules prepared in Example 3 have a better appearance than those prepared in Comparative Example 1, overcoming the problems of AITC microcapsules easily agglomerating, yellowing, and becoming sticky. This may be because the inclusion of AITC in CD reduces the CD's ability to bind to water molecules.

[0095] 2. Application in pork

[0096] The knife, cutting board, and sealed bag were first disinfected with 75% alcohol. The microcapsules prepared in Example 3, the microcapsules prepared in Comparative Example 1, and the blank microcapsules were sterilized by irradiation with ultraviolet light for 30 minutes. After ultraviolet irradiation, the pork was cut into approximately 50-gram cubes and randomly divided into four treatment groups for a total of five sampling days. Each treatment group had three pork samples per sampling day, and 0.2-0.4 g of microcapsules were placed in a microcapsule sustained-release bag with a length of 6 cm and a width of 3 cm. The treatment methods were as follows: (1) Blank (Control): only pork; (2) Pork + blank microcapsule sustained-release bag (Blank mps); (3) Pork + microcapsule sustained-release bag prepared in Comparative Example 1 (AITC mps); (4) Pork + microcapsule sustained-release bag prepared in Example 3 (CEO / AITC CD mps). The sealing strip of the polyethylene ziplock bag was used to press the sealing line of the sustained-release bag so that it was suspended on the top of the ziplock bag to avoid direct contact with the pork. The four treatment groups were stored in a −4°C refrigerator and tested on 0d, 3d, 6d, 9d, and 12d.

[0097] 1) TBARS value in pork (TBARS value is used to identify the degree of oxidation of meat)

[0098] The results are as follows Figure 5 shown.

[0099] Lipid oxidation is an important factor associated with the deterioration of food quality. Measurement of TBARS is a common method for evaluating oxidative changes in food during storage. The TBARS content reflects the content of lipid peroxides and malondialdehyde, a degradation product of peroxides, formed during the oxidation of polyunsaturated fatty acids, and is widely used as an evaluation indicator of the degree of lipid oxidation. Initially, the TBARS value of all samples was approximately 0.2 mg MDA / Kg. The blank group and the blank microcapsule group began to increase rapidly from the third day, increasing to 0.58±0.10 mg MDA / Kg and 0.57±0.11 mg MDA / Kg, respectively. From the 9th day, the TBARS value of the microcapsule group prepared in Comparative Example 1 began to increase significantly, reaching 0.94±0.03 mg MDA / Kg. On the 12th day, the TBARS value of the microcapsule group prepared in Example 3 was significantly lower than that of the other treatments (P<0.05), at 0.81±0.07 mg MDA / Kg. The results showed that compared with other treatments, the microcapsules prepared in Example 3 effectively reduced the TBARS value in meat during the entire storage process and could effectively extend the shelf life of pork.

[0100] 2) pH

[0101] The results are as follows Figure 6 shown

[0102] There is a strong relationship between pH and microorganisms. This may be because the protein in meat is decomposed into alkaline ammonia and amines by microorganisms and enzymes during storage. These substances will accumulate over time, causing the pH to rise. The pH value of fresh pork is between 5.8 and 6.2, and the pH value of spoiled pork is above 6.7. The results show that Figure 6 The pH values ​​of the different treatments were not significant at the beginning of storage (P>0.05). The pH of all samples gradually increased after 3 days of storage. The blank group and the blank microcapsule treatment group showed deterioration on the 6th day, with values ​​of 6.78±0.034 and 6.72±0.049, respectively. The microcapsule treatment group prepared in Comparative Example 1 and the microcapsule treatment group prepared in Example 3 extended the shelf life of the meat to the 12th day, with values ​​of 6.68±0.018 and 6.61±0.012, respectively. The results showed that the microcapsules delayed the increase in pH value in pork during refrigeration, among which the microcapsules prepared in Example 3 showed a better preservation effect.

[0103] 3) Color measurement

[0104] The results are as follows Figure 7 shown.

[0105] The color of fresh pork is an important factor in determining consumers' purchasing desire. The L* value is related to the glossiness of pork. Figure 7As shown in Figure A, the L* values ​​of all treatment groups decreased with storage time, with the blank group and the blank microcapsule-treated group experiencing the fastest decline, reaching 40.21±0.31 and 40.78±0.21 on day 12. The L* values ​​of the microcapsules prepared in Comparative Example 1 and Example 3 decreased to 43.96±0.27 and 44.37±0.14, respectively, with no significant differences (p>0.05). However, there was a significant difference compared to the blank group (p<0.05), indicating that the microcapsules were more successful in preserving the color of the pork.

[0106] The a* value represents red, which is mainly related to the myoglobin in meat. In the presence of oxygen, myoglobin is bright red. In meat that has been exposed to air for a long time and is not fresh, myoglobin and oxymyoglobin will turn into metmyoglobin, making the meat appear brown. In the absence of oxygen, metmyoglobin is purple-red. Figure 7 As shown in Figure B, a* values ​​showed a generally downward trend. In the blank group, a* values ​​dropped to 3.04±0.31 on day 12, followed by the blank microcapsule-treated group, which dropped to 3.21±0.24, showing no significant difference from the blank group. In the microcapsule group prepared in Comparative Example 1, a* values ​​dropped to 3.99±0.27, while in the microcapsule group prepared in Example 3, a* values ​​dropped to 5.15±0.22 on day 12, showing significant differences from the blank group.

[0107] The b* value represents the yellowness. Undesirable brown discoloration of meat during storage is usually related to the oxidation of myoglobin in metMb on the meat surface. Figure 7 As shown in Figure C, except for the microcapsule-treated group prepared in Example 3, which showed an initial increase followed by a decrease, the b* values ​​of the chilled pork in the other treatment groups continued to decline. The b* value of the microcapsule-treated group prepared in Example 3 was 7.65±0.34 on day 12, which was significantly different from the other three groups (p<0.05). Compared with the blank group and the blank microcapsule group, the microcapsule group prepared in Example 3 significantly improved the color of the chilled pork. These results demonstrate that CEO is a potential natural preservative that can inhibit discoloration in chilled pork.

[0108] 4) TVB-N

[0109] The results are as follows Figure 8 shown

[0110] TVB-N is an index used to judge the freshness of meat. The higher the content (mg / 100g), the less fresh the meat is. According to the Chinese standard GB / T9959.2-2008 (Fresh and frozen lean pork, cuts), if the TVB-N content of refrigerated pork exceeds the upper limit of 15mg / 100g, it is considered to be spoiled. Figure 8The TVB-N values ​​of the four treatments are shown. At the beginning of storage, the TVB-N values ​​of fresh pork ranged from 4.37 to 4.87 mg / 100 g, and there was no significant change between the samples with different treatments (P>0.05). In the later stage of storage, the sustained release of phenolic substances can effectively inhibit the formation of amine compounds and prolong the storage time of pork. By the end of storage, the TVB-N value of the microcapsules prepared in Example 3 was still within the specified range, at 15.89±0.41 mg / 100 g. Therefore, compared with the blank group, the shelf life of the meat treated with the microcapsules prepared in Example 3 was extended by 6 days. These results indicate that the microcapsules prepared in Example 3 can delay the increase in the TVB-N value of pork during refrigeration.

[0111] Experiment 3

[0112] Figure 9 、 Figure 10 EE and solubility results after changing the wall material raw materials, proportions, and core-to-wall ratios.

[0113] Figure 9 、 10 The EE and solubility of the wall materials were measured for the microcapsules prepared with different wall materials. By comparing them, it can be seen that the EE and solubility of the microcapsules prepared with maltodextrin and gum arabic powder are the highest, so the wall materials are prepared according to this ratio.

[0114] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0115] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A plant essential oil microcapsule, characterized in that: The invention comprises the following components in parts by weight: 2-3 parts of allyl isothiocyanate, 1-3 parts of eugenol, 0.5-1.5 parts of thymol, 1-3 parts of cuminaldehyde, 4-6 parts of cyclodextrin and 8-11 parts of gum arabic; The preparation method of the plant essential oil microcapsules comprises the following steps: (1) Preparation of AITC / CD inclusion complex (11) Configure a mass concentration of 3~5% CD aqueous solution; (12) CD While the aqueous solution is being stirred, a mixture of allyl isothiocyanate and ethanol is added dropwise thereto and stirred for 3-5 hours; A mixture of allyl isothiocyanate and ethanol, CD The volume ratio of the aqueous solution is 1:1~1:4; (13) Filter the residue and then dry it to obtain dry AITC / CD inclusion compound powder; (2) Preparation of microcapsule emulsion (21) Preparation containing AITC / CD Add Tween 80 to the aqueous solution of inclusion compound and gum arabic, stir and dissolve, and use as the wall material solution; Among them, AITC / CD The mass concentration of inclusion complex and gum arabic is 23-27%; Including AITC / CD AITC / CD The mass ratio of inclusion complex to gum arabic was 1:1; (22) Mix three plant essential oils: eugenol, thymol, and cuminaldehyde to obtain a composite essential oil; (23) mixing the composite essential oil and the wall material solution in a volume ratio of 1:4 to 1:8 and homogenizing to obtain a microcapsule emulsion; (3) Preparation of microcapsules The microcapsule emulsion is spray-dried.

2. A plant essential oil microcapsule according to claim 1, characterized in that, The invention comprises the following components in parts by weight: 2.5 parts of allyl isothiocyanate, 2 parts of eugenol, 1 part of thymol, 2 parts of cuminaldehyde, 5 parts of cyclodextrin and 10 parts of gum arabic.

3. The method for preparing a plant essential oil microcapsule according to any one of claims 1 and 2, wherein: The steps include: (1) Preparation of AITC / CD inclusion complex (11) Configure a mass concentration of 3~5% CD aqueous solution; (12) CD While the aqueous solution is being stirred, a mixture of allyl isothiocyanate and ethanol is added dropwise thereto and stirred for 3-5 hours; A mixture of allyl isothiocyanate and ethanol, CD The volume ratio of the aqueous solution is 1:1~1:4; (13) Filter the residue and then dry it to obtain dry AITC / CD inclusion compound powder; (2) Preparation of microcapsule emulsion (21) Preparation containing AITC / CD Add Tween 80 to the aqueous solution of inclusion compound and gum arabic, stir and dissolve, and use as the wall material solution; Among them, AITC / CD The mass concentration of inclusion complex and gum arabic is 23-27%; Including AITC / CD AITC / CD The mass ratio of inclusion complex to gum arabic was 1:1; (22) Mix three plant essential oils: eugenol, thymol, and cuminaldehyde to obtain a composite essential oil; (23) mixing the composite essential oil and the wall material solution in a volume ratio of 1:4 to 1:8 and homogenizing to obtain a microcapsule emulsion; (3) Preparation of microcapsules The microcapsule emulsion is spray-dried.

4. The preparation method according to claim 3, wherein In the step (12), the rotation speed under stirring is 800-1000 rpm and the temperature is 45-55°C.

5. The preparation method according to claim 3, wherein In the step (12), the volume ratio of allyl isothiocyanate to ethanol is 1:1 to 1:

4.

6. The preparation method according to claim 3, wherein The mass ratio of eugenol, thymol and cuminaldehyde in step (22) is 2:1:2~3:2:

3.

7. The preparation method according to claim 3, wherein The homogenization parameters in step (23) are: 750-850 r / min for 5-7 min.

8. The preparation method according to claim 3, wherein The spray drying parameters in step (3) are: inlet air temperature 180°C, outlet air temperature 80°C.

9. Use of the plant essential oil microcapsules according to any one of claims 1 or 2 in preserving fresh meat of livestock and poultry.

10. The use according to claim 9, characterized in that It is used to reduce the TBARS value in meat, delay the increase of pH value, inhibit the color change of meat, and delay the increase of TVB-N value.

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