Slow-release tea leaf preservative and preparation method thereof

Abstract

The application provides a slow-release tea preservative and a preparation method thereof, and belongs to the technical field of preservatives.The preparation method comprises the following steps: S1, dissolving a vitamin E derivative in oil, stirring and uniformly mixing to prepare an oil phase; S2, dissolving a hydrophilic emulsifier in water, adding sodium alginate, stirring and uniformly mixing to prepare an aqueous phase; S3, adding the oil phase into the aqueous phase, high-speed emulsifying to form an emulsion, heating to a reaction temperature, dropwise adding a calcium chloride solution, cooling and solidifying, filtering, and drying to obtain the slow-release tea preservative.The prepared VE citric acid ester derivative can significantly improve the antioxidant performance of VE, obviously improve the stability of VE to acid and heat, is not prone to oxidation and deterioration, has good sterilization, antibiosis, bacteriostasis and anti-inflammatory effects, and the prepared VE derivative can be slowly released due to the slow-release microcapsule structure, thereby achieving long-acting preservation.

Description

Technical Field

[0001] This invention relates to the field of preservative technology, specifically to a slow-release tea preservative and its preparation method. Background Technology

[0002] Currently, the production of tea in my country, especially premium green tea, is mainly concentrated in the spring. However, the process from processing and storage to sales and consumption involves a long period. Due to the influence of factors such as temperature, humidity, moisture, oxygen, and light, the internal components of tea undergo a series of changes, leading to a decline in quality. Nowadays, with the improvement of people's living standards, the requirements for tea quality are becoming increasingly higher, and the effectiveness of tea preservation further affects the sales price of tea and the profits of enterprises.

[0003] The Chinese invention patent authorization announcement number is CN100382724C, entitled "Tea Preservative", which discloses "a tea preservative composed of an active desiccant, sodium metabisulfite, sodium ascorbate, and ascorbic acid, with a mass ratio of 15:15:60:10. The active desiccant of this preservative is montmorillonite."

[0004] Another Chinese invention patent, CN101828605A, discloses a tea preservative, its preparation method, and its application. This preservative comprises iron powder, ferrous chloride, sodium bicarbonate, fumaric acid, zeolite, and an active desiccant, with the following mass ratio: 20-25 parts iron powder, 10-15 parts ferrous chloride, 20-25 parts sodium bicarbonate, 5-10 parts fumaric acid, 15-20 parts zeolite, and 2-5 parts active desiccant. The existing technology has the following problems: First, because it uses montmorillonite as an active desiccant, this preservative absorbs moisture and easily expands, failing to effectively preserve the tea; second, its preservation effect on tea is not very effective, easily shortening the preservation time or deteriorating the quality of the tea; third, the preservatives in the existing technology are disposable and cannot be reused. Summary of the Invention

[0005] The purpose of this invention is to propose a slow-release tea preservative and its preparation method. The VE citrate derivative obtained by esterifying fat-soluble vitamin E with citric acid can not only significantly improve the antioxidant properties of VE, but also significantly improve its stability to acid and heat, making it less prone to oxidative deterioration. It also has good bactericidal, antibacterial, bacteriostatic, and anti-inflammatory effects. At the same time, the slow-release microcapsule structure prepared by this invention allows the obtained VE derivative to be released slowly, thus playing a long-term preservation role.

[0006] The technical solution of this invention is implemented as follows:

[0007] This invention provides a vitamin E derivative having the structure shown in Formula I:

[0008]

[0009] This invention further protects a method for preparing the above-mentioned vitamin E derivative, the synthetic route of which is as follows:

[0010]

[0011] As a further improvement of the present invention, the method includes the following steps: mixing vitamin E and citric acid to undergo an esterification reaction to obtain the vitamin E derivative.

[0012] This invention further protects a method for preparing a slow-release tea preservative, comprising the following steps:

[0013] S1. Preparation of the oil phase: The above-mentioned vitamin E derivative is dissolved in oil and stirred until homogeneous to obtain the oil phase;

[0014] S2. Preparation of the aqueous phase: Dissolve the hydrophilic emulsifier in water, add sodium alginate, stir and mix evenly to obtain the aqueous phase;

[0015] S3. Preparation of slow-release tea preservative: The oil phase obtained in step S1 is added to the aqueous phase obtained in step S2, emulsified at high speed to form an emulsion, heated to the reaction temperature, calcium chloride solution is added dropwise, cooled and solidified, filtered, and dried to obtain the slow-release tea preservative.

[0016] As a further improvement of the present invention, the oil is a vegetable oil or an animal oil, selected from at least one of corn oil, soybean oil, sesame oil, rapeseed oil, lard, fish oil, olive oil, and algal oil.

[0017] As a further improvement of the present invention, the hydrophilic emulsifier is selected from at least one of sodium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium hexadecylbenzenesulfonate, sodium hexadecylbenzenesulfonate, sodium hexadecyl sulfate, sodium octadecylbenzenesulfonate, sodium octadecylsulfonate, and Tween-80.

[0018] As a further improvement of the present invention, the content of vitamin E derivative in the oil phase in step S1 is 7-12 wt%.

[0019] As a further improvement of the present invention, the content of sodium alginate in the aqueous phase in step S2 is 10-20 wt%; and the content of the hydrophilic emulsifier is 2-4 wt%.

[0020] As a further improvement of the present invention, the high-speed emulsification conditions in step S3 are 10000-20000 r / min for 5-10 min; the heating to 60-90℃ is carried out, and the concentration of the calcium chloride solution is 2-5 wt%.

[0021] This invention further protects a slow-release tea preservative prepared by the above-described preparation method.

[0022] This invention offers the following beneficial effects: Vitamin E, also known as tocopherol, is a lipid-based antioxidant. It comprises four types: α, β, γ, and δ, with dextrorotatory α-tocopherol exhibiting the highest activity. VE counteracts oxygen free radicals, interrupting lipid peroxidation chain reactions and protecting cell membranes, intracellular nucleic acids, and other biomolecules from attack and damage. VE is stable to acids and heat, but it is easily decomposed and deteriorated in oxygen, light, and alkaline environments. Relatively speaking, esterified VE is more stable than free VE. Because the phenolic hydroxyl groups of esterified VE are protected, its chemical structure is more robust, and it possesses many functions that VE does not have, such as anti-cancer effects, thus broadening the application areas of VE.

[0023] This invention produces a vitamin E citrate derivative by esterifying fat-soluble vitamin E with citric acid. This derivative not only significantly improves the antioxidant properties of vitamin E, but also significantly enhances its stability to acid and heat, making it less prone to oxidative deterioration. It also has excellent bactericidal, antibacterial, bacteriostatic, and anti-inflammatory effects. Furthermore, the invention is prepared into a sustained-release microcapsule structure, which allows the obtained vitamin E derivative to be released slowly, thus providing a long-lasting preservation effect. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1

[0026] This embodiment provides a method for preparing a vitamin E derivative:

[0027] The synthesis route is as follows:

[0028]

[0029] Preparation method: 1 mol of vitamin E and 4 mol of citric acid were dissolved in DMSO-ethanol solvent (volume ratio 3:1), lipase was added, the mixture was heated to 50℃ and reacted for 0.5 h. Water was added to precipitate the mixture, and the mixture was filtered to obtain the vitamin E derivative.

[0030] Example 2

[0031] This embodiment provides a method for preparing a vitamin E derivative: 1 mol of vitamin E and 6 mol of citric acid are dissolved in DMF-ethanol solvent (volume ratio 3:1), lipase is added, the mixture is heated to 60°C, reacted for 1 hour, water is added to precipitate, and the mixture is filtered to obtain the vitamin E derivative.

[0032] Example 3

[0033] This embodiment provides a method for preparing a vitamin E derivative: 1 mol of vitamin E and 5 mol of citric acid are dissolved in a DMAC-ethanol solvent (volume ratio of 3:1), lipase is added, the mixture is heated to 55°C, reacted for 1 hour, water is added to precipitate the product, and the mixture is filtered to obtain the vitamin E derivative.

[0034] Example 4

[0035] This embodiment provides a method for preparing a slow-release tea preservative, including the following steps:

[0036] S1. Preparation of the oil phase: The vitamin E derivative obtained in Example 1 was dissolved in fish oil and stirred until homogeneous to obtain the oil phase, the content of the vitamin E derivative being 7 wt%.

[0037] S2. Preparation of the aqueous phase: Sodium dodecyl sulfonate was dissolved in water, sodium alginate was added, and the mixture was stirred and mixed evenly to obtain the aqueous phase. The content of sodium alginate was 10 wt% and the content of sodium dodecyl sulfonate was 2 wt%.

[0038] S3. Preparation of slow-release tea preservative: Add 50g of the oil phase obtained in step S1 to the aqueous phase obtained in step S2, emulsify at 10000r / min for 5min to form an emulsion, heat to 60℃, add 2wt% calcium chloride solution dropwise, cool and solidify, filter, and dry to obtain the slow-release tea preservative.

[0039] Example 5

[0040] This embodiment provides a method for preparing a slow-release tea preservative, including the following steps:

[0041] S1. Preparation of the oil phase: The vitamin E derivative obtained in Example 2 was dissolved in rapeseed oil and stirred until homogeneous to obtain the oil phase, the content of vitamin E derivative being 12 wt%.

[0042] S2. Preparation of the aqueous phase: Sodium hexadecyl sulfate was dissolved in water, sodium alginate was added, and the mixture was stirred and mixed evenly to obtain the aqueous phase. The content of sodium alginate was 20 wt% and the content of sodium hexadecyl sulfate was 4 wt%.

[0043] S3. Preparation of slow-release tea preservative: Add 50g of the oil phase obtained in step S1 to the aqueous phase obtained in step S2, emulsify at 20000r / min for 10min to form an emulsion, heat to 90℃, add 5wt% calcium chloride solution dropwise, cool and solidify, filter, and dry to obtain the slow-release tea preservative.

[0044] Example 6

[0045] This embodiment provides a method for preparing a slow-release tea preservative, including the following steps:

[0046] S1. Preparation of the oil phase: The vitamin E derivative obtained in Example 3 was dissolved in corn oil and stirred until homogeneous to obtain the oil phase, the content of vitamin E derivative being 9 wt%.

[0047] S2. Preparation of aqueous phase: Dissolve Tween-80 in water, add sodium alginate, stir and mix evenly to obtain an aqueous phase with sodium alginate content of 15 wt% and Tween-80 content of 3 wt%.

[0048] S3. Preparation of slow-release tea preservative: Add 50g of the oil phase obtained in step S1 to the aqueous phase obtained in step S2, emulsify at 15000r / min for 7min to form an emulsion, heat to 75℃, add 3.5wt% calcium chloride solution dropwise, cool and solidify, filter, and dry to obtain the slow-release tea preservative.

[0049] Test Example 1

[0050] One 5g packet of the slow-release tea preservative prepared in Examples 4-6 of this invention was added to 1kg of dried tea leaves. A blank group was also set up, without the addition of the slow-release tea preservative. All groups were stored for 20 days in an environment with a temperature of 24-27℃, humidity of 65-75%, and oxygen content of 27-30%. Samples were then taken out and their microbial content was tested; the results are shown in Table 1. After further storage for 3 months, a comparative example group was added, in which 5g of the vitamin E derivative prepared in Example 3 was added. Samples were then taken out and their microbial content was tested; the results are shown in Table 2.

[0051] Table 1

[0052] Group Coliform bacteria (CFU / g) Total bacterial count (CFU / g) Example 4 <![CDATA[(3.22±0.11)×10 2* ]]> <![CDATA[(7.23±0.14)×10 3* ]]> Example 5 <![CDATA[(3.10±0.16)×10 2* ]]> <![CDATA[(7.20±0.12)×10 3* ]]> Example 6 <![CDATA[(2.97±0.13)×10 2* ]]> <![CDATA[(7.11±0.10)×10 3* ]]> Blank group <![CDATA[(6.27±1.09)×10 6 ]]> <![CDATA[(7.25±1.12)×10 7 ]]>

[0053] Note: * indicates p<0.05, compared with Comparative Example 1 (blank group).

[0054] As shown in Table 1 above, the slow-release tea preservative prepared by the present invention can significantly achieve antibacterial and bacteriostatic effects. In humid environments with high oxygen content and high temperature, bacteria are prone to grow. Adding the tea preservative prepared by the present invention can significantly preserve the tea and extend its shelf life.

[0055] Table 2

[0056] Group Coliform bacteria (CFU / g) Total bacterial count (CFU / g) Example 4 <![CDATA[(1.72±0.10)×10 3* ]]> <![CDATA[(4.42±0.09)×10 4* ]]> Example 5 <![CDATA[(1.67±0.08)×10 3* ]]> <![CDATA[(4.36±0.10)×10 4* ]]> Example 6 <![CDATA[(1.61±0.09)×10 3* ]]> <![CDATA[(4.25±0.12)×10 4* ]]> Comparative Example 1 <![CDATA[(4.58±0.42)×10 5 ]]> <![CDATA[(2.74±0.25)×10 7 ]]> Blank group <![CDATA[(7.24±1.45)×10 8 ]]> <![CDATA[(9.27±1.72)×10 9 ]]>

[0057] Note: * indicates p<0.05, compared with Comparative Example 1 (blank group).

[0058] As shown in Table 2 above, the slow-release tea preservative prepared in this invention still exhibits significant antibacterial effects after 3 months of storage, which is significantly better than that of Comparative Example 1. It is evident that the VE citrate derivative prepared by the present invention through the esterification reaction of fat-soluble vitamin E with citric acid not only significantly improves the antioxidant properties of VE but also significantly enhances its stability to acid and heat, making it less prone to oxidative deterioration. Furthermore, it possesses excellent bactericidal, antibacterial, bacteriostatic, and anti-inflammatory effects. Simultaneously, the slow-release microcapsule structure prepared in this invention allows the obtained VE derivative to be released slowly, achieving a long-lasting preservation effect.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a slow-release tea preservative, characterized in that, Includes the following steps: S1. Preparation of the oil phase: Dissolve the vitamin E derivative in oil, stir and mix evenly to obtain the oil phase; The vitamin E derivative has the structure shown in Formula I: ， Formula I; Its synthetic route is as follows: ； The preparation method includes the following steps: mixing vitamin E and citric acid to undergo an esterification reaction to obtain the vitamin E derivative; S2. Preparation of the aqueous phase: Dissolve the hydrophilic emulsifier in water, add sodium alginate, stir and mix evenly to obtain the aqueous phase; S3. Preparation of slow-release tea preservative: The oil phase obtained in step S1 is added to the aqueous phase obtained in step S2, emulsified at high speed to form an emulsion, heated to the reaction temperature, calcium chloride solution is added dropwise, cooled and solidified, filtered, and dried to obtain the slow-release tea preservative. The oil is a vegetable oil or an animal oil, selected from at least one of corn oil, soybean oil, sesame oil, rapeseed oil, lard, fish oil, olive oil, and algae oil; The hydrophilic emulsifier is selected from at least one of sodium dodecylbenzene sulfonate, sodium dodecylbenzene sulfonate, sodium hexadecylbenzene sulfonate, sodium hexadecyl sulfonate, sodium hexadecyl sulfate, sodium octadecylbenzene sulfonate, and Tween-80. The content of vitamin E derivative in the oil phase in step S1 is 7-12 wt%; In step S2, the content of sodium alginate in the aqueous phase is 10-20 wt%; the content of the hydrophilic emulsifier is 2-4 wt%. The high-speed emulsification conditions in step S3 are 10000-20000 r / min for 5-10 min; the heating to 60-90℃; and the concentration of the calcium chloride solution is 2-5 wt%. A slow-release tea preservative was prepared using this method.

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