Antioxidant with slow release effect as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of food preservation, and particularly relates to an antioxidant with a slow release effect and a preparation method and application thereof.The antioxidant comprises an essential oil microcapsule and a wrapping layer, the essential oil microcapsule comprises a core material and a wall material, and the core material comprises, by weight, 1.5-8.1 parts of thymol and 84.6-90.3 parts of spearmint oil; 3.05 to 9.21 parts by weight of eugenol and 1.5 to 4.2 parts by weight of ginger oil. The wall material is a beta-cyclodextrin derivative, the wrapping layer is a multi-layer composite film, and a plurality of holes are distributed in each layer. The antioxidant can be used for slowly releasing essential oil through humidity response, so that the quality deterioration speed of fresh meat in the storage process can be obviously delayed, and the antioxidant and antibacterial capabilities of the fresh meat are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of food preservation, and in particular relates to an antioxidant with a slow-release effect, a preparation method and an application thereof. Background Art

[0002] Fresh meat is susceptible to microbial contamination and fat oxidation during storage, leading to quality deterioration. Existing preservation technologies mainly rely on chemical preservatives, but the presence of chemical additives runs counter to consumers' pursuit of natural and green products. In recent years, plant essential oils have been used in a variety of products for their antioxidant and antibacterial properties due to their natural antioxidant and antibacterial properties. Natural compounds often require high concentrations to achieve the same effect as commercial additives, which may have adverse effects on the product or even cause toxicity. In addition, essential oils are highly volatile, have a short duration of action, and may affect the smell of the product when used in high concentrations. Therefore, how to improve the antioxidant capacity of fresh meat and achieve an increase in the antibacterial rate without affecting the sensory properties of the meat is an urgent problem that needs to be solved. Summary of the Invention

[0003] (1) Purpose of the invention

[0004] The purpose of the present invention is to provide an antioxidant with a sustained-release effect, a preparation method and an application thereof. The antioxidant can respond to humidity and slowly release essential oils, which can significantly slow down the quality deterioration of fresh meat during storage and enhance its antioxidant and antibacterial capabilities.

[0005] (2) Technical solution

[0006] To solve the above problems, the first aspect of the present invention provides an antioxidant with a sustained-release effect, wherein the antioxidant comprises essential oil microcapsules and a wrapping layer, wherein the essential oil microcapsules comprise a core material and a wall material, wherein the core material comprises the following components:

[0007] 1.5-8.1 parts by weight of thymol, 84.6-90.3 parts by weight of spearmint oil, 3.05-9.21 parts by weight of eugenol, and 1.5-4.2 parts by weight of ginger oil. The core material preferably comprises 4.9 parts by weight of thymol, 86.3 parts by weight of spearmint oil, 4.7 parts by weight of eugenol, and 3.1 parts by weight of ginger oil.

[0008] The wall material is a beta-cyclodextrin derivative, and the wrapping layer is a multi-layer composite film, with a plurality of holes distributed in each layer.

[0009] Furthermore, the wall material includes at least one of β-cyclodextrin, hydroxypropyl-β-cyclodextrin and sulfobutyl-β-cyclodextrin.

[0010] Furthermore, the composite film includes three layers, which are a polyethylene terephthalate layer, a polyacrylate adhesive layer and a polyethylene layer from the outside to the inside.

[0011] Furthermore, each layer is distributed with a number of circular holes, each with a diameter of 0.15 to 0.25 mm.

[0012] The second aspect of the present invention provides a method for preparing an antioxidant with a sustained-release effect as described in any one of the above descriptions, comprising:

[0013] S1, mixing thymol, spearmint oil, eugenol, and ginger oil to obtain a compound essential oil, wherein the compound essential oil comprises: 1.5-8.1 parts by weight of thymol, 84.6-90.3 parts by weight of spearmint oil, 3.05-9.21 parts by weight of eugenol, and 1.5-4.2 parts by weight of ginger oil, wherein the compound essential oil is used as a core material;

[0014] S2, mixing the β-cyclodextrin derivative with water at a preset mass-to-volume ratio, stirring in a water bath until completely dissolved, cooling to the embedding temperature, allowing to stand, and filtering to obtain a clear cyclodextrin supersaturated solution;

[0015] S3, mixing the compound essential oil and anhydrous ethanol in a preset volume ratio, and adding the mixture dropwise to the supersaturated cyclodextrin solution at a preset speed, stirring, cooling, standing, vacuumizing, washing, and drying to obtain essential oil microcapsules;

[0016] S4, wrapping the essential oil microcapsules with a wrapping layer and sealing the microcapsules to obtain an antioxidant.

[0017] Furthermore, in the step S2, the mass volume ratio of the β-cyclodextrin derivative to water is 1:10 to 14, expressed in g / mL, to ensure that a supersaturated cyclodextrin solution is obtained, preferably 1:12.

[0018] Furthermore, in the step S3, the volume ratio of the compound essential oil to anhydrous ethanol is 1:18 to 22, preferably 1:20, and the dropping speed is 0.8 to 1.2 mL / min.

[0019] Furthermore, the wrapping layer includes three layers of composite membranes, each layer is provided with a plurality of holes, such as circular holes, with a pore diameter of 0.15 to 0.25 mm, preferably a pore diameter of 0.2 mm.

[0020] Furthermore, in step S1, the water bath temperature is 75-85°C, preferably 80°C.

[0021] The third aspect of the present invention provides an application of any one of the above-described sustained-release antioxidants in the preservation of fresh meat, which is particularly suitable for maintaining the quality of meat under different packaging conditions (conventional preservation, high oxygen conditioning, and heat shrink packaging).

[0022] (3) Beneficial effects

[0023] The above technical solution of the present invention has the following beneficial technical effects: The present invention provides an antioxidant with a sustained-release effect, its preparation method, and application. The antioxidant comprises essential oil microcapsules and a coating layer, which can respond to humidity and slowly release essential oils, significantly slowing the rate of quality deterioration of fresh meat during storage, thereby improving its antioxidant and antibacterial capabilities. The essential oil microcapsules comprise a core material and a wall material, and the coating layer is a multi-layer composite film. The preparation method of the antioxidant comprises: using natural ingredients such as thymol, spearmint oil, eugenol, and ginger oil that inhibit various free radicals and bacteria as the core material, and mixing the ingredients in the following weight parts: 1.5-8.1 parts by weight of thymol, 84.6-90.3 parts by weight of spearmint oil, 3.05-9.21 parts by weight of eugenol, and 1.5-4.2 parts by weight of ginger oil to obtain a compound essential oil. The above four essential oils have strong inhibitory effects on specific free radicals and bacteria. Then prepare cyclodextrin supersaturated solution, the compound essential oil and anhydrous ethanol are mixed in a preset volume ratio to ensure that the compound essential oil components are melted, and the resulting mixed solution is added dropwise to embed in cyclodextrin supersaturated solution, until the solution is cooled and placed in a refrigerator to stand, vacuum filtration, and finally the solid powder (essential oil microcapsules) obtained by filtration is spread in a glass culture dish, placed in a drying oven and dried to constant weight, and the dried microcapsules are wrapped in a composite film, i.e., a humidity-responsive sustained-release broad-spectrum antioxidant is obtained. When meat is mature, moisture inside the meat seeps out, and ambient humidity increases, and water molecules are adsorbed on the surface and pores of cyclodextrin, and are combined with the hydroxyl (-OH) groups of β-cyclodextrin by hydrogen bonds, resulting in molecular conformational expansion and instability, thereby causing cyclodextrin pores to increase, and essential oil release rate is improved, and antibacterial on demand is achieved by the humidity response characteristics of wall material cyclodextrin. The antioxidant prepared by the present invention can effectively improve the antioxidant and antibacterial capabilities of the product during storage for fresh meat, and does not affect meat sensory properties while realizing antibacterial rate improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the composition of an antioxidant product with a sustained-release effect of the present invention;

[0025] Figure 2 DPPH scavenging ability graph of thymol, spearmint oil, eugenol, and ginger oil in specific embodiments of the present invention;

[0026] Figure 3 This is a graph showing the DPPH scavenging ability of the mixed essential oils of thymol, spearmint oil, eugenol, and ginger oil in Example 1 of the present invention;

[0027] Figure 4 The diagrams are of meat color changes during storage in Examples 7-9 and Comparative Examples 3-5;

[0028] Figure 5This is a flow chart of the preparation method of the antioxidant with sustained-release effect of the present invention;

[0029] Figure 6 This is a schematic diagram of the packaging of the finished product of the antioxidant with sustained-release effect of the present invention. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0031] The present invention addresses the defects of the prior art in that essential oils are volatile, the microcapsule encapsulation efficiency is low, and the microcapsule lacks environmental responsiveness. In the first aspect, the present invention provides an antioxidant with a slow-release effect, such as Figure 1As shown, the antioxidant of the present invention includes essential oil microcapsules and a coating layer. The essential oil microcapsules include a core material and a wall material. The core material uses thymol, spearmint oil, eugenol, and ginger oil, which are natural ingredients that inhibit various free radicals and bacteria. Ginger essential oil is derived from the rhizome extract of the ginger plant Zingiber officinale and has a spicy aroma; thymol is a natural monoterpene phenol component with broad-spectrum antibacterial activity; spearmint oil mainly contains L-carvone as the main component, which can inhibit bacteria such as Escherichia coli and Staphylococcus aureus; eugenol is the main active substance in plants such as cloves and cinnamon, and has both anti-inflammatory and antioxidant properties. In terms of antibacterial mechanism, these four essential oils all work by destroying the integrity of microbial cell membranes: hydrophobic components insert into the phospholipid bilayer, increasing membrane permeability, leading to the leakage of intracellular ions and small molecules, causing membrane potential collapse, ATPase activity inhibition, protein dysfunction and metabolic interruption, and ultimately cell death. Thymol mainly removes DPPH free radicals, spearmint oil mainly removes hydroxyl radicals and superoxide anion radicals, eugenol mainly removes lipid peroxyl radicals, hydroxyl radicals and DPPH free radicals, and ginger oil mainly acts on superoxide anion radicals and hydroxyl radicals. The contents of each component in the core material are as follows: 1.5-8.1 parts by weight of thymol, 84.6-90.3 parts by weight of spearmint oil, 3.05-9.21 parts by weight of eugenol, and 1.5-4.2 parts by weight of ginger oil. By compounding the above four ingredients in proportion, the antibacterial rate is improved without affecting the sensory properties of the meat. The wall material is a β-cyclodextrin derivative, and the wall material includes at least one of β-cyclodextrin, hydroxypropyl-β-cyclodextrin and sulfobutyl-β-cyclodextrin. The wrapping layer is a multi-layer composite film, with a number of holes distributed in each layer. The composite film consists of three layers: from the outside to the inside, a polyethylene terephthalate (PET) layer, a polyacrylate (PRA) adhesive layer, and a polyethylene (PE) layer. By combining microcapsules with the three-layer perforated composite film, the microcapsules (essential oil microcapsules) can slowly release essential oils in response to humidity in the environment without direct contact with the product. Each layer is distributed with several circular holes with a pore size of 0.15 to 0.25 mm, making the product suitable for fresh meat preservation scenarios such as conventional storage, heat shrink packaging, and high-oxygen modified oxygen packaging. Figure 6 This is a schematic diagram of the finished packaging of the antioxidant with sustained-release effect of the present invention. During the storage of fresh meat products, the humidity gradually increases. This product can enable the essential oil to be slowly released into the environment through humidity response. The present invention has developed an essential oil microcapsule antioxidant with both high encapsulation rate and humidity-responsive sustained-release characteristics. It is adaptable to a variety of packaging forms and becomes the key to improving the antioxidant and antibacterial properties of fresh meat products. Humidity-responsive sustained-release mechanism: The microcapsules are stable at low humidity. When the meat matures, the ambient humidity rises, the microcapsule wall material cyclodextrin absorbs water and expands, the pores increase, and the essential oil release rate increases with the increase in ambient humidity, achieving on-demand antibacterial effect.

[0032] The second aspect of the present invention provides a method for preparing an antioxidant with a sustained-release effect as described in any one of the above descriptions, the method comprising:

[0033] S1. Mixing thymol, spearmint oil, eugenol, and ginger oil to obtain a compound essential oil, wherein the weight proportions of the components in the compound essential oil are as follows: 1.5-8.1 parts by weight of thymol, 84.6-90.3 parts by weight of spearmint oil, 3.05-9.21 parts by weight of eugenol, and 1.5-4.2 parts by weight of ginger oil.

[0034] S2, mixing a β-cyclodextrin derivative with water in a predetermined mass-to-volume ratio, stirring in a water bath until completely dissolved, cooling to the embedding temperature, and allowing to stand to obtain a supersaturated cyclodextrin solution; the mass-to-volume ratio of the β-cyclodextrin derivative to water is 1:10-14 (g / mL), preferably 1:12. The water bath temperature is 75-85°C, preferably 80°C.

[0035] S3, mixing the compound essential oil and anhydrous ethanol in a preset volume ratio, and adding the mixture dropwise to the supersaturated cyclodextrin solution, stirring, cooling, standing, vacuuming, washing and drying to obtain essential oil microcapsules; in the S3 step, the volume ratio of the compound essential oil and anhydrous ethanol is 1:18 to 22, preferably 1:20, and the mixture is added dropwise at a uniform speed, and the dropping speed is 0.8 to 1.2 mL / min.

[0036] S4, wrapping the essential oil microcapsules with a wrapping layer and sealing the layers to obtain the antioxidant. The wrapping layer comprises three layers of composite membrane, each layer having a plurality of circular holes with a pore diameter of 0.15 to 0.25 mm, preferably 0.2 mm.

[0037] A third aspect of the present invention provides a use of any one of the above-described antioxidants with a sustained-release effect in preserving fresh meat.

[0038] The preparation is described in detail below with reference to specific examples.

[0039] like Figure 2 As shown, the present invention first measured the DPPH scavenging ability of thymol, spearmint oil, eugenol, and ginger oil, and the DPPH scavenging ability was referenced to the "GB / T 39100-2020" standard. Figure 2 The concentrations of the different essential oils were standardized using a density-mass conversion formula, and it was preliminarily determined that 1.5-8.1 parts by weight of thymol, 84.6-90.3 parts by weight of spearmint oil, 3.05-9.21 parts by weight of eugenol, and 1.5-4.2 parts by weight of ginger oil could achieve the best antioxidant and antibacterial effects.

[0040] Example 1

[0041] According to the above Figure 2 Thymol, spearmint oil, eugenol, and ginger oil were mixed at the following mass ratios according to the preliminarily determined concentrations to obtain a compound essential oil. The mass percentages of the components in the compound essential oil were as follows: 4.9 parts by weight of thymol, 86.3 parts by weight of spearmint oil, 4.7 parts by weight of eugenol, and 3.1 parts by weight of ginger oil. The scavenging ability of the compound essential oil at different concentrations of DPPH was tested with reference to GB / T 39100-2020. Figure 3 By regulating the ratio of essential oil concentration, the DPPH scavenging rate was significantly improved, higher than that of the four components acting alone.

[0042] Example 2

[0043] This embodiment differs from Example 1 only in that the mass percentages of the components in the compound essential oil are: 7.4 parts by weight of thymol, 92.4 parts by weight of spearmint oil, and 0.2 parts by weight of eugenol, and ginger oil is not added. The DPPH scavenging abilities are shown in Table 1.

[0044] Example 3

[0045] The only difference between this example and Example 1 is that the mass percentages of the components in the compound essential oil are: 7 parts by weight of thymol, 92 parts by weight of spearmint oil, no eugenol, and 1 part by weight of ginger oil. The DPPH scavenging ability is shown in Table 1.

[0046] Example 4

[0047] The only difference between this example and Example 1 is that the mass percentages of the components in the compound essential oil are: 88 parts by weight of thymol, no spearmint oil, 10 parts by weight of eugenol, and 2 parts by weight of ginger oil. The DPPH scavenging ability is shown in Table 1.

[0048] Example 5

[0049] The only difference between this embodiment and embodiment 1 is that the mass percentages of the components in the compound essential oil are: no thymol, 94 parts by weight of spearmint oil, 2 parts by weight of eugenol, and 4 parts by weight of ginger oil. The DPPH scavenging ability is shown in Table 1.

[0050] Comparative Example 1

[0051] This embodiment differs from Example 1 only in that the mass percentages of the components in the compound essential oil are: 6.9 parts by weight of thymol, 91.8 parts by weight of spearmint oil, 0.135 parts by weight of eugenol, and 1.165 parts by weight of lemon essential oil. The DPPH scavenging abilities are shown in Table 1.

[0052] Comparative Example 2

[0053] This example differs from Example 1 only in that the mass percentages of the components in the compounded essential oil are: 6.9 parts by weight of thymol, 91.8 parts by weight of spearmint oil, 0.135 parts by weight of rosemary essential oil, and 1.165 parts by weight of ginger oil. The DPPH scavenging abilities are shown in Table 1.

[0054] Table 1 Comparison of clearance rates of various embodiments and comparative examples

[0055]

[0056]

[0057] As can be seen from Table 1, the composite essential oil prepared in Example 1 has a stronger DPPH scavenging ability, which is stronger than the composite essential oils prepared in Examples 2-5 and Comparative Examples 1 and 2.

[0058] Example 6

[0059] On the basis of Example 1, β-cyclodextrin was mixed with distilled water at a ratio of 1:12 (g / mL), stirred in an 80°C water bath until completely dissolved, cooled to 55°C, and allowed to stand to obtain a supersaturated solution of cyclodextrin. The compound essential oil obtained in Example 1 was mixed with anhydrous ethanol at a ratio of 1:20 (v / v), added dropwise to the saturated solution of cyclodextrin at a rate of 1 mL / min, and stirred for 10 min. It was then cooled to 3°C and allowed to stand for 24 hours. After vacuum filtration, it was washed three times with anhydrous ethanol and deionized water, and dried at 40°C to constant weight to obtain compound essential oil microcapsules (essential oil microcapsules).

[0060] 20g of compound essential oil microcapsules were wrapped with a composite film with a surface circular hole with a pore diameter of 0.2mm and a material of PE, PRA, and PET three-layer composite film with a size of 4cm×3cm, and then sealed with a heat sealer to obtain a humidity-responsive sustained-release broad-spectrum antioxidant.

[0061] Accurately weigh 50 g of the compound essential oil prepared in Example 1, place it in a 100 mL small beaker, and place it in a 4 ° C, 50% RH environment. The mass is accurately measured 4 times on the first, third, fifth, and tenth days. Weigh 50 g of the compound essential oil microcapsules prepared in Example 6 as a reference substance, bake to constant weight before accurately measuring the mass, and perform a control test in the same way. By weighing the remaining mass, the volatility can be obtained, as shown in Table 2.

[0062] Table 2 Changes in volatility of compound essential oils and compound essential oil microcapsules during storage

[0063]

[0064] From the conclusions drawn in Table 2, it can be seen that this product has sustained release within 10 days.

[0065] According to the Technical Requirements for Chilled Meat Processing (GB / T 22576-2008): For chilled beef, it is required that the product be stored in an environment of 0-4°C and about 80% RH during processing, transportation, and sales. Therefore, the prepared samples were tested under different packaging conditions, as shown in Examples 7-9.

[0066] Example 7

[0067] Take fresh beef of about 15 cm × 10 cm × 10 cm, place the antioxidant prepared in Example 6 on the upper surface of the meat, and place the treated beef in an environment of 4°C and 80% RH.

[0068] Example 8

[0069] Take fresh beef of about 15 cm × 10 cm × 10 cm, place the antioxidant prepared in Example 6 on the upper surface of the meat, shrink-wrap the treated beef, and place it in an environment of 4°C and 80% RH.

[0070] Example 9

[0071] Take fresh beef of about 15cm×10cm×10cm, place the antioxidants prepared in Example 6 on the upper surface of the meat, and then subject the treated beef to high oxygen (gas volume fraction of 80% O2, 15% CO2, 5% N2) gas conditioning treatment and place it in a 4°C, 80% RH environment.

[0072] Comparative Example 3

[0073] The only difference from Example 7 is that the antioxidant prepared in Example 6 is not used.

[0074] Comparative Example 4

[0075] The only difference from Example 8 is that the antioxidant prepared in Example 6 is not used.

[0076] Comparative Example 5

[0077] The only difference from Example 9 is that the antioxidant prepared in Example 6 is not used.

[0078] This test example tests the total bacterial count, peroxide value, malondialdehyde content, meat color and sensory evaluation of beef treated in Examples 7, 8, 9 and Comparative Examples 3, 4 and 5, as follows:

[0079] The beef treated according to Examples 7, 8, 9 and Comparative Examples 3, 4, and 5 were stored in an environment of 4°C and 50% RH. The total colony count, peroxide value, malondialdehyde content, meat color, and sensory evaluation were measured at the same storage time points, and the differences in the above indicators during storage were compared between the different groups of products.

[0080] Total colony count, peroxide value, and malondialdehyde content were determined according to GB 4789.2-2022, GB 5009.227-2016, and GB 5009.227-2016, respectively. Three samples were tested in each treatment group, and the three results were averaged. The total colony count was the average of the logarithms of the results. Sensory evaluation was conducted by 15 professionals using visual, tactile, and olfactory testing to assess the texture, color, and odor of each sample. The evaluation items were scored on a 10-point scale, with scores from high to low being: good (10.0-8.1), good (8.0-6.1), fair (6.0-4.1), poor (4.0-2.1), and extremely poor (2.0-0). The total score was used as the criterion for evaluation, with a maximum score of 40.

[0081] The total number of colonies in each example is shown in Table 3, unit: 1g (CFU g -1 ).

[0082] Table 3 Changes in total bacterial count during storage of Examples 7, 8, 9 and Comparative Examples 3, 4, and 5

[0083] Example Day 1 Day 3 Day 5 Day 10 Example 7 4.26 3.9 5.08 7.42 Comparative Example 3 4.25 4.43 5.43 7.97 Example 8 4.44 4.19 5.33 6.44 Comparative Example 4 4.38 4.55 6.08 6.69 Example 9 4.19 4.22 4.59 4.74 Comparative Example 5 4.23 4.44 5.00 5.94

[0084] The peroxide value of each embodiment is shown in Table 4, unit: mg / g.

[0085] Table 4 Changes in peroxide value during storage of Examples 7, 8, 9 and Comparative Examples 3, 4, and 5

[0086] Day 1 Day 3 Day 5 Day 10 Example 7 0.81 0.87 1.08 1.21 Comparative Example 3 0.82 0.88 1.18 1.47 Example 8 0.79 0.85 0.91 1.03 Comparative Example 4 0.85 0.92 1.12 1.22 Example 9 0.75 0.81 0.83 0.91 Comparative Example 5 0.78 0.84 0.86 1.13

[0087] The malondialdehyde content of each example is shown in Table 5, unit: nmol / g.

[0088] Table 5 Changes in malondialdehyde content during storage in Examples 7, 8, 9 and Comparative Examples 3, 4, and 5

[0089]

[0090]

[0091] Flesh color Figure 4 The sensory evaluation scores are shown in Table 6.

[0092] Table 6 Sensory evaluation scores of Examples 7, 8, 9, Comparative Examples 3, 4, and 5 during storage

[0093] Day 1 Day 3 Day 5 Day 10 Example 7 35 23 15 8 Comparative Example 3 35 18 8 4 Example 8 37 26 19 15 Comparative Example 4 36 20 15 9 Example 9 38 33 29 23 Comparative Example 5 38 26 20 15

[0094] Tables 3-6 show that after 10 days of storage, the total colony count, peroxide value, and malondialdehyde content of the three groups of fresh beef samples with different packaging all showed a gradual increase. The total colony count reflects the degree of microbial contamination in the beef and can provide a direct indicator of its hygienic condition and freshness. The peroxide value is an early indicator of fat oxidation in the beef, with the higher the value, the more severe the initial stage of fat oxidation. The malondialdehyde content indicates the depth of fat oxidation in the beef and can reflect the final product of lipid oxidation and the degree of deterioration. The total sensory evaluation score gradually decreased, and the meat color gradually darkened, indicating that product quality deteriorated with prolonged storage. The total colony count, peroxide value, and malondialdehyde content of Examples 7, 8, and 9 containing this product were significantly lower than those of Comparative Examples 3, 4, and 5, and the sensory evaluation scores were higher than those of Comparative Examples 3, 4, and 5. The meat color was also better than those of Comparative Examples 3, 4, and 5, indicating that this product can effectively maintain product quality. On the tenth day, the total bacterial count and peroxide value of Examples 7, 8, and 9 were still lower than those of Comparative Examples 3, 4, and 5, and the sensory evaluation scores were higher than those of Comparative Examples 3, 4, and 5, indicating that the shelf life of the products is at least ten days. These experimental results demonstrate that the present invention can effectively extend the quality retention period of fresh meat and has sustained-release properties.

[0095] The present invention provides a sustained-release antioxidant, its preparation method, and application. This antioxidant can respond to humidity and slowly release essential oils, effectively delaying the quality degradation of fresh meat during storage and enhancing its antioxidant and antibacterial capabilities. The preparation method involves preparing compound essential oil microcapsules using an aqueous solution saturation method, using natural ingredients such as thymol, spearmint oil, eugenol, and ginger oil, which inhibit various free radicals and bacteria, as core materials and β-cyclodextrin derivatives as wall materials. Distilled water and cyclodextrin derivatives are added in specific proportions to prepare a supersaturated dextrin solution. The solution is heated to 80°C with stirring to dissolve the cyclodextrin in the water, and then cooled to the embedding temperature. According to a specific volume ratio of the compound essential oil to anhydrous ethanol, the compound essential oil-ethanol solution is added dropwise at a uniform speed to the cyclodextrin aqueous solution for embedding, the solution is cooled and placed in a refrigerator for 24 hours, and then vacuum filtered. The filter residue is dissolved with anhydrous ethanol and then vacuum filtered. The residue is washed and filtered multiple times with deionized water to remove the essential oil attached to the outside of the cyclodextrin, and dried to a constant weight. The dried microcapsules are encapsulated in a three-layer perforated composite film of PE, PRA, and PET to obtain a humidity-responsive sustained-release broad-spectrum antioxidant. The invention has a sustained-release property and can be used in fresh meat products to effectively improve the antioxidant and antibacterial capabilities of the product during storage.

[0096] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. And the obvious changes or modifications derived therefrom are still within the scope of protection created by the present invention. It should be understood that the above specific embodiments of the present invention are merely used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the scope of protection of the present invention. In addition, the claims attached to the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the attached claims, or the equivalent forms of such scope and boundaries.

Claims

1. An antioxidant with a sustained-release effect, characterized in that: The antioxidant includes essential oil microcapsules and a wrapping layer. The essential oil microcapsules include a core material and a wall material. The core material includes the following components: 1.5-8.1 parts by weight of thymol, 84.6-90.3 parts by weight of spearmint oil, 3.05-9.21 parts by weight of eugenol, and 1.5-4.2 parts by weight of ginger oil. The wall material is a β-cyclodextrin derivative. The wrapping layer is a multilayer composite film, and a plurality of holes are distributed in each layer.

2. The antioxidant with sustained release according to claim 1, characterized in that The wall material includes at least one of β-cyclodextrin, hydroxypropyl-β-cyclodextrin and sulfobutyl-β-cyclodextrin.

3. The antioxidant with sustained release according to claim 1, characterized in that The composite film comprises three layers, which are a polyethylene terephthalate layer, a polyacrylate adhesive layer and a polyethylene layer from the outside to the inside.

4. The antioxidant with sustained release according to claim 1, characterized in that There are several circular holes distributed on each layer, with a hole diameter of 0.15 to 0.25 mm.

5. A method for preparing an antioxidant with a sustained-release effect as claimed in claims 1 to 4, characterized in that: include: S1, mixing thymol, spearmint oil, eugenol, and ginger oil to obtain a compound essential oil, wherein the compound essential oil comprises: 1.5-8.1 parts by weight of thymol, 84.6-90.3 parts by weight of spearmint oil, 3.05-9.21 parts by weight of eugenol, and 1.5-4.2 parts by weight of ginger oil; S2, mixing the β-cyclodextrin derivative with water at a preset mass-to-volume ratio, stirring in a water bath until completely dissolved, cooling to the embedding temperature, allowing to stand, and filtering to obtain a clear cyclodextrin supersaturated solution; S3, mixing the compound essential oil and anhydrous ethanol in a preset volume ratio, and adding the mixture dropwise to the supersaturated cyclodextrin solution, stirring, cooling, standing, vacuumizing, washing, and drying to obtain essential oil microcapsules; S4, wrapping the essential oil microcapsules with a wrapping layer and sealing the microcapsules to obtain an antioxidant.

6. A method for preparing an antioxidant with a sustained-release effect as claimed in claim 5, characterized in that: In the step S2, the mass volume ratio of the β-cyclodextrin derivative to water is 1:10-14, and the unit is g / mL.

7. A method for preparing an antioxidant with a sustained-release effect as claimed in claim 5, characterized in that: In the step S3, the volume ratio of the compound essential oil to anhydrous ethanol is 1:18-22, and the dropping speed is 0.8-1.2 mL / min.

8. A method for preparing an antioxidant with a sustained-release effect as claimed in claim 5, characterized in that: The wrapping layer includes three layers of composite membranes, each layer is distributed with a number of circular holes, and the hole diameter is 0.15-0.25 mm.

9. A method for preparing an antioxidant with a sustained-release effect as claimed in claim 5, characterized in that: In the step S1, the water bath temperature is 75-85°C.

10. Use of the antioxidant with sustained release effect according to claims 1 to 4 in preserving fresh meat.

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