阅读说明：本技术 一种具有高效附载和缓释乙烯的环糊精载体及其制备方法 (Cyclodextrin carrier with efficient ethylene loading and sustained-release functions and preparation method thereof ) 是由 黄强 黎晗 张斌 扶雄 于 2019-09-04 设计创作，主要内容包括：本发明公开了一种具有高效附载和缓释乙烯的环糊精载体制备方法,包括如下步骤：(1)将α-环糊精与碱性物质溶于水中,配成α-环糊精母液；(2)将挥发的甲醇或乙醇气体与α-环糊精母液混合,进行反应,得到α-环糊精晶体,研磨晶体得α-环糊精晶体粉末；(3)将α-环糊精晶体粉末置于高压反应釜中,抽真空,通入乙烯,进行高压反应,反应结束后,去除残留乙烯,得到附载有乙烯的α-环糊精晶体粉末。该方法可明显提高乙烯的包埋率,采用传统α-环糊精附载乙烯,包埋率约为2.50％,本方法乙烯的包埋率≥40％；该方法制备的载体吸附乙烯后稳定性较好,在25℃下贮存15天后仍有较高的包埋率。(The invention discloses a preparation method of a cyclodextrin carrier with efficient ethylene loading and sustained-release, which comprises the following steps: (1) dissolving alpha-cyclodextrin and an alkaline substance in water to prepare alpha-cyclodextrin mother liquor; (2) mixing the volatilized methanol or ethanol gas with the alpha-cyclodextrin mother liquor, reacting to obtain alpha-cyclodextrin crystals, and grinding the crystals to obtain alpha-cyclodextrin crystal powder; (3) and (3) placing the alpha-cyclodextrin crystal powder in a high-pressure reaction kettle, vacuumizing, introducing ethylene, performing high-pressure reaction, and removing residual ethylene after the reaction is finished to obtain the ethylene-loaded alpha-cyclodextrin crystal powder. The method can obviously improve the embedding rate of ethylene, the traditional alpha-cyclodextrin is adopted to carry ethylene, the embedding rate is about 2.50 percent, and the embedding rate of the ethylene is more than or equal to 40 percent; the carrier prepared by the method has good stability after adsorbing ethylene, and still has high embedding rate after being stored for 15 days at 25 ℃.)

1. A preparation method of cyclodextrin carrier with high-efficiency ethylene loading and slow-release is characterized by comprising the following steps:

(1) dissolving alpha-cyclodextrin and an alkaline substance in water to prepare alpha-cyclodextrin mother liquor;

(2) mixing the volatilized methanol or ethanol gas with the alpha-cyclodextrin mother liquor, reacting to obtain alpha-cyclodextrin crystals, and grinding the crystals to obtain alpha-cyclodextrin crystal powder;

(3) and (3) placing the alpha-cyclodextrin crystal powder in a high-pressure reaction kettle, vacuumizing, introducing ethylene, performing high-pressure reaction, and removing residual ethylene after the reaction is finished to obtain the ethylene-loaded alpha-cyclodextrin crystal powder.

2. Preparation according to claim 1The method is characterized in that the alkaline substances in the step (1) are NaOH, KOH and C₇H₅KO₂One or more than two of them.

3. The preparation method according to claim 2, wherein the concentration of the alpha-cyclodextrin mother liquor in the step (1) is 0.01-0.15M, preferably 0.05-0.1M.

4. The preparation method according to claim 3, wherein the molar ratio of the alpha-cyclodextrin to the basic substance in the step (1) is 1 (6-10).

5. The method according to claim 4, wherein the molar ratio of the alpha-cyclodextrin to the basic substance in the step (1) is 1:8, and the concentration of the alpha-cyclodextrin mother liquor is 0.0675M.

6. The production method according to any one of claims 1 to 5, wherein the reaction conditions in the step (2) are: the open container containing the alpha-cyclodextrin mother liquor is placed in a closed container containing methanol or ethanol, and the volume of the methanol or the ethanol contained in the closed container is more than 2.5 times of the volume of the alpha-cyclodextrin mother liquor.

7. The method according to any one of claims 1 to 5, wherein the reaction temperature in the step (2) is 25 to 50 ℃ and the reaction time is 5 to 15 days.

8. The preparation method according to any one of claims 1 to 5, wherein the alpha-cyclodextrin crystals in the step (2) are washed with methanol or ethanol, dried in vacuum at 30 to 60 ℃ for 10 to 30 hours, and then ground and sieved with a 100 to 250 mesh sieve; and (3) absorbing and removing residual ethylene by bromine water.

9. The preparation method according to any one of claims 1 to 5, wherein the placing amount of the alpha-cyclodextrin crystal powder in the step (3) is 20 to 30 percent of the volume of the reaction kettle, and the vacuum degree is-0.01 to-0.1 MPa; the conditions of the high-pressure reaction are as follows: the pressure is 1.0-1.6 MPa, the reaction temperature is 20-30 ℃, and the reaction time is 15-25 h.

10. A cyclodextrin carrier prepared by the process of any one of claims 1 to 9.

Technical Field

The invention relates to a method for efficiently and stably loading ethylene gas by utilizing alpha-cyclodextrin crystals, which relates to the embedding slow release of the ethylene gas and belongs to the fields of food preservation and chemical engineering.

Background

Ethylene is a plant hormone, is an important component for regulating and controlling plant maturity, and has the functions of promoting cell expansion, inducing flower bud differentiation, accelerating fruit ripening and the like. In the field of modified atmosphere storage of fruits and vegetables, ethylene is widely used to promote fruit ripening.

The gas is usually stored and transported in high pressure resistant cylinders, with the risk of leakage and explosion during use. Adsorption of the gas in a porous solid medium reduces this risk and has a slow release profile. Partial fruits such as bananas, mangoes and the like are not completely ripe before being harvested, and the solid powder adsorbed with the ethylene gas can be placed in an environment in the process of storage or transportation, so that the ethylene gas is slowly released, the concentration of ethylene in the surrounding atmosphere is continuously regulated and controlled, and the aim of controlling the ripening of fruits and vegetables is fulfilled.

At present, cyclodextrin is used for adsorbing ethylene gas, and the preparation method mainly adopts solid embedding. At 25 ℃, putting cyclodextrin powder into a high-pressure reaction kettle, vacuumizing the reaction kettle, introducing ethylene gas, and reacting for 120 hours under 1.5 MPa. After the reaction is finished, carrying out vacuum filtration on the sample to obtain the cyclodextrin adsorbed with ethylene, drying at room temperature to constant weight, packaging with a sealing bag, and storing in a dry, low-temperature and dark environment. The embedding rate of ethylene was tested to be 2.50% (w/w). (Ho, B.T., Bhandari, B.R. (2016.) Novel soluble encapsulation of ethylene gas using amophorus alpha-cyclodextin and the release catalysts, J.Agric.food.chem,64, 3318-.

Disclosure of Invention

In order to overcome the defects and shortcomings in the prior art, the invention aims to provide a carrier material capable of efficiently carrying ethylene gas and improving the stability of the ethylene gas.

The invention uses alpha-cyclodextrin and sodium hydroxide (NaOH), potassium hydroxide (KOH) or potassium benzoate (C)₇H₅KO₂) The solid is dissolved together and then recrystallized to prepare alpha-cyclodextrin crystal, NaOH, KOH or C is utilized₇H₅KO₂To remove hydroxyl in alpha-cyclodextrinHydrogen and, at the same time, Na⁺Or K⁺With exposed-O^-And coordinating to form a new porous structure. The diffusion of the volatile methanol or ethanol gas causes the produced alpha-cyclodextrin crystals to precipitate out of solution. During the drying process, methanol or ethanol volatilizes, and a porous network structure is formed inside the material. The invention takes the alpha-cyclodextrin crystal as the embedding wall material to adsorb the ethylene gas, has the characteristics of high adsorption efficiency, high sample recovery rate, good compound stability and greenness and no toxicity, particularly obviously improves the adsorption quantity of the ethylene and the stability of the compound compared with the prior art, and provides a safer and more convenient selection for controlled atmosphere storage in the fruit and vegetable transportation process.

A preparation method of cyclodextrin carrier with high-efficiency ethylene loading and slow-release comprises the following steps:

(1) dissolving alpha-cyclodextrin and an alkaline substance in water to prepare alpha-cyclodextrin mother liquor;

(2) mixing the volatilized methanol or ethanol gas with the alpha-cyclodextrin mother liquor, reacting to obtain alpha-cyclodextrin crystals, and grinding the crystals to obtain alpha-cyclodextrin crystal powder;

(3) and (3) placing the alpha-cyclodextrin crystal powder in a high-pressure reaction kettle, vacuumizing, introducing ethylene, performing high-pressure reaction, and removing residual ethylene after the reaction is finished to obtain the ethylene-loaded alpha-cyclodextrin crystal powder.

Preferably, the alkaline substance in step (1) is NaOH, KOH and C₇H₅KO₂One or more than two of them.

Preferably, the concentration of the alpha-cyclodextrin mother liquor in the step (1) is 0.01-0.15M, and preferably 0.05-0.1M.

Preferably, the molar ratio of the alpha-cyclodextrin to the alkaline substance in the step (1) is 1 (6-10).

Preferably, the molar ratio of the alpha-cyclodextrin to the alkaline substance in the step (1) is 1:8, and the concentration of the alpha-cyclodextrin mother liquor is 0.0675M.

Preferably, the reaction conditions of step (2) are: the open container containing the alpha-cyclodextrin mother liquor is placed in a closed container containing methanol or ethanol, and the volume of the methanol or the ethanol contained in the closed container is more than 2.5 times of the volume of the alpha-cyclodextrin mother liquor.

Preferably, the reaction temperature in the step (2) is 25-50 ℃, and the reaction time is 5-15 days.

Preferably, the alpha-cyclodextrin crystal in the step (2) is washed by methanol or ethanol, dried in vacuum at the drying temperature of 30-60 ℃ for 10-30 h, and ground and sieved by a sieve of 100-250 meshes; and (3) absorbing and removing residual ethylene by bromine water.

Preferably, the placing amount of the alpha-cyclodextrin crystal powder in the step (3) is 20 to 30 percent of the volume of the reaction kettle, and the vacuum degree is between-0.01 and-0.1 Mpa; the conditions of the high-pressure reaction are as follows: the pressure is 1.0-1.6 MPa, the reaction temperature is 20-30 ℃, and the reaction time is 15-25 h.

The method can be used for preparing cyclodextrin carrier.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the invention can obviously improve the embedding rate of the ethylene. The traditional alpha-cyclodextrin is adopted to carry ethylene, the embedding rate is about 2.50 percent (w/w), and the embedding rate of the ethylene is more than or equal to 40 percent (w/w).

(2) The carrier prepared by the invention has good stability after adsorbing ethylene. The embedding rate is still higher (more than or equal to 20 percent) after the storage for 15 days at the temperature of 4 ℃ and 25 ℃.

Drawings

FIG. 1 is a standard curve of peak area versus ethylene mass.

Detailed Description

The present invention will be described in further detail below with reference to examples, comparative examples, and the accompanying drawings, but the embodiments of the present invention are not limited thereto.