An ethylene adsorption coating slurry applied to fruit and vegetable preservation and a preparation method and application thereof

Abstract

The application belongs to the technical field of fruit and vegetable preservation, and particularly relates to an ethylene adsorption coating slurry applied to fruit and vegetable preservation and a preparation method and application thereof. The ethylene adsorption coating slurry comprises a film forming agent and an ethylene absorber, the film forming agent is a cellulose nanofiber suspension, and the ethylene absorber is a porous material loaded with potassium permanganate. The obtained ethylene adsorption coating effectively increases the contact area of potassium permanganate and ethylene, improves the ethylene absorption efficiency, and has a significant preservation effect on fruits and vegetables, and can be applied to various forms and sizes of fruit and vegetable preservation packaging.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fruit and vegetable preservation, and particularly relates to an ethylene adsorption coating slurry applied to fruit and vegetable preservation and a preparation method and application thereof. BACKGROUND

[0002] Ethylene is a plant hormone released by fruits and vegetables, and is related to the whole process of growth, ripening and germination of fruits and vegetables. The amount of ethylene released by fruits and vegetables themselves gradually increases with the extension of storage time. In addition to accelerating the ripening of fruits and vegetables, it also causes over-ripening and even rotting of fruits and vegetables, shortens the shelf life, and causes economic losses. Therefore, using ethylene synthesis inhibitors or scavengers to delay the ripening of fruits and vegetables is the key to postharvest preservation of fruits and vegetables. Ethylene absorbers are one of the methods commonly used to reduce or eliminate ethylene at present. Ethylene absorbers can be divided into physical adsorbents and chemical reaction agents. The physical adsorbents mainly include activated carbon, mineral powder, molecular sieve and synthetic resin with fine porous structure. This kind of adsorbent has no selectivity to ethylene, has fast adsorption rate, is less affected by temperature, but is easy to reach saturation, and the adsorption of physical adsorbent to ethylene molecules only relies on intermolecular force, which is weak adsorption and easy to desorb. The chemical reaction agent commonly used is potassium permanganate loaded on activated carbon, alumina, molecular sieve and other carriers. It is often used in the form of bags in commerce, and preserves fruits and vegetables by oxidizing ethylene. However, the carrier of potassium permanganate is mostly in the form of particles or powder, which is easy to adhere to fruits and vegetables. If it is packed in bags, it will affect the diffusion rate of gas and reduce the ethylene elimination efficiency. Moreover, the action area of solid preservative is limited, which is only suitable for small-bag or box-packaged high-quality fruit and vegetable preservation. If it is applied to the preservation of fruits and vegetables in foam boxes, paper boxes and other large packages, it cannot completely absorb harmful gases, so the preservation effect is not obvious. Chinese patent application file CN111778770A provides an inorganic coating gradient gas regulating fruit and vegetable preservation paper and a preparation method. The fruit and vegetable preservation paper is prepared by roller printing three layers of coating and spraying a phytic acid layer on the surface of the base paper, so that the storage environment of fruits and vegetables is always in a relatively constant humidity environment, and the ratio of oxygen and carbon dioxide is balanced, while ethylene is discharged, slowing down the cell respiration of fruits and vegetables, and achieving the purpose of preservation. However, the ethylene discharge efficiency is low, and the preservation effect is not obvious. At present, there are also studies on mixing porous materials such as zeolite and silicon oxide powder loaded with potassium permanganate with ink / adhesive to prepare preservation packaging such as corrugated paper boxes. Although this method increases the contact area with ethylene, the voids are blocked by the adhesive after the porous material is blended with the film-forming agent and adhesive, which greatly affects the adsorption performance. At the same time, there is a problem of large pollution in the production process. Therefore, how to provide an efficient and green ethylene elimination method is a technical problem to be solved by those skilled in the art. SUMMARY

[0003] The primary purpose of the present application is to provide a new ethylene adsorption coating slurry for fruit and vegetable preservation in view of the shortcomings and deficiencies of the existing fruit and vegetable preservation technology.

[0004] Another purpose of the present application is to provide a preparation method of the ethylene adsorption coating slurry.

[0005] Still another purpose of the present application is to provide the application of the ethylene adsorption coating slurry.

[0006] One purpose of the present application is achieved by the following technical solutions:

[0007] An ethylene adsorption coating slurry for fruit and vegetable preservation, comprising a film-forming agent and an ethylene adsorption agent.

[0008] As a preferred embodiment, the film-forming agent is a cellulose nanofiber suspension, and the ethylene adsorption agent is a porous material loaded with potassium permanganate.

[0009] Cellulose nanofiber is a nanoscale particle composed of cellulose molecules, with a size usually between 1 and 100 nanometers. It is a nanoscale particle derived from natural plant cellulose such as wood, cotton, and rice husk, with excellent renewability, biocompatibility, and mechanical properties, as well as extremely high specific surface area. Since cellulose nanofiber is insoluble in water, after film formation, cellulose nanofiber interweaves together to form a three-dimensional network structure. Therefore, after mixing the porous material loaded with potassium permanganate with the cellulose nanofiber suspension, the voids on the surface of the porous material will not be blocked, effectively increasing the contact area between potassium permanganate and ethylene.

[0010] As a preferred embodiment, the cellulose nanofiber is one or more of TEMPO-oxidized cellulose nanofiber and quaternized cellulose nanofiber.

[0011] TEMPO-oxidized cellulose nanofiber is obtained by oxidizing cellulose with 2,2,6,6-tetramethylpiperidine-1-oxide radical (TEMPO). Quaternized cellulose nanofiber is obtained by alkalizing the surface hydroxyl groups of cellulose nanofiber and then etherifying with an ammonium-containing etherification reagent.

[0012] The TEMPO-oxidized cellulose nanofiber and quaternized cellulose nanofiber used in the present application can be commercially available products or can be prepared from microcrystalline cellulose. The specific preparation method is not limited, and any preparation method that can obtain TEMPO-oxidized cellulose nanofiber and quaternized cellulose nanofiber is acceptable.

[0013] Further preferably, the cellulose nanofiber is a mixture of TEMPO-oxidized cellulose nanofiber and quaternary aminated cellulose nanofiber. The mixture of TEMPO-oxidized cellulose nanofiber and quaternary aminated cellulose nanofiber has a better ethylene adsorption effect when the suspension formed by the mixture is mixed with the ethylene adsorbent.

[0014] Preferably, the cellulose nanofiber suspension is formed by dispersing cellulose nanofiber in water, and the mass percentage concentration of the cellulose nanofiber suspension is 0.05-0.30%.

[0015] Further preferably, the mass percentage concentration of the cellulose nanofiber suspension is 0.10-0.20%.

[0016] Preferably, the mass percentage concentration of potassium permanganate in the ethylene adsorption coating slurry is 0.05-0.50%.

[0017] Further preferably, the mass percentage concentration of potassium permanganate in the ethylene adsorption coating slurry is 0.08-0.30%.

[0018] Preferably, 1-20 g of potassium permanganate is loaded per 100 g of porous material in the ethylene adsorbent. Further preferably, 2-10 g of potassium permanganate is loaded per 100 g of porous material.

[0019] Preferably, the porous material is one or more of zeolite powder, silicon oxide, sepiolite, activated carbon, alumina, and diatomite.

[0020] Zeolite powder is a powdery crystalline mineral material formed by grinding natural zeolite rock, and is a Na, Ca, Ba silicate with rich crystal water, and the main components are Al2O3 and SiO2. Silicon oxide has a microporous structure, a high specific surface area, and good adsorption performance. Sepiolite is a fibrous hydrous magnesium silicate, and the sepiolite crystal has a chain structure and good adsorption performance. Activated carbon is a powdery or granular porous amorphous carbon with strong adsorption capacity, and has a developed pore structure and a large specific surface area, and strong specific adsorption capacity. Alumina is a chemically inert adsorbent with high adsorption capacity, and has a large surface area and multiple capillary channels. Diatomite is a porous material with a micron-sized pore size, and the particle surface has countless small pores arranged in a regular and orderly manner in a circular and needle shape, and has strong physical adsorption performance.

[0021] Further preferably, the porous material is zeolite powder.

[0022] Preferably, the preparation method of the porous material loaded with potassium permanganate comprises: soaking the porous material in a saturated potassium permanganate solution, filtering and drying to obtain the porous material loaded with potassium permanganate.

[0023] Another object of the present application is achieved by the following technical solutions:

[0024] A preparation method of ethylene adsorption coating slurry applied to fruit and vegetable preservation, comprising the following steps:

[0025] (1) Soaking the porous material in a saturated potassium permanganate solution, filtering and drying to obtain an ethylene absorber;

[0026] As a preferred, the porous material is soaked in the saturated potassium permanganate solution for 1-4 hours.

[0027] As a preferred, the obtained porous material loaded with potassium permanganate is dried at 50-65℃.

[0028] As a preferred, the obtained porous material loaded with potassium permanganate is dried for 2-3 hours.

[0029] (2) Preparing a cellulose nanofiber suspension with a suitable concentration;

[0030] (3) Mixing the ethylene absorber with the cellulose nanofiber suspension, stirring uniformly to obtain the ethylene adsorption coating slurry.

[0031] A third object of the present application is achieved by the following technical solutions:

[0032] The above ethylene adsorption coating slurry is coated on the inner layer of the fruit and vegetable outer packaging, and dried to obtain a fruit and vegetable outer packaging with an ethylene adsorption coating. The fruit and vegetable outer packaging can be listed as corrugated cartons, foam boxes, packaging paper boxes, packaging bags, etc.; the ethylene adsorption coating has high ethylene absorption capacity and can be applied to various forms of packaging for fruit and vegetable preservation.

[0033] As a preferred, the coating amount of the ethylene adsorption coating slurry (calculated based on the potassium permanganate content) is 0.2-2 g / m 2 .

[0034] Further preferably, the coating amount of the ethylene adsorption coating slurry (calculated based on the potassium permanganate content) is 0.4-1.2 g / m 2 .

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] 1. Cellulose nanofiber is used as a film former, and after film formation, the cellulose nanofiber interweaves to form a three-dimensional network structure. After mixing the porous material loaded with potassium permanganate with the cellulose nanofiber suspension, the voids on the surface of the porous material will not be blocked, effectively increasing the contact area between potassium permanganate and ethylene;

[0037] 2、Cellulose has excellent renewability, biocompatibility and biodegradability, and the use of cellulose greatly reduces the pressure of resource shortage and environmental pollution; the cellulose is further nanofiber in the application, which can further fully exert the advantages of high strength, high modulus and high specific surface area;

[0038] 3、The ethylene adsorption coating slurry prepared by the application can be coated on the inner layer of fruit and vegetable outer packaging such as corrugated cartons, foam boxes, packaging cartons and packaging bags, and is suitable for various forms and sizes of fruit and vegetable preservation packaging.

[0039] 4、The ethylene adsorption coating obtained after drying the ethylene adsorption coating slurry prepared by the application has high ethylene absorption capacity, and has a significant preservation effect on fruits and vegetables. DETAILED DESCRIPTION

[0040] The technical solutions of the application will be further described and illustrated below by specific examples. It should be understood that the specific examples described herein are only used to help understand the application and are not used to limit the application. In the following examples, the experimental methods are conventional unless otherwise specified. In the following examples, the materials, etc. are commercially available unless otherwise specified. In the following examples, the instruments and equipment used are recommended by the manufacturer unless otherwise specified.

[0041] The TEMPO cellulose nanofiber suspension used in the examples and comparative examples was purchased from Zhongshan Nanofiber New Material Co., Ltd., and the solid content was 2.5%. The carboxymethyl cellulose and hydroxyethyl cellulose used were purchased from Shanxi Jinyang Pharmaceutical Auxiliary Material Co., Ltd.

[0042] Preparation method of quaternary amine cellulose nanofiber:

[0043] 2g of NaOH and 2g of paper pulp were sequentially added to a three-necked round-bottom flask containing 200mL of deionized water, and after the NaOH solid was completely dissolved, 29g of 2,3-epoxypropyltrimethylammonium chloride solid was quickly added, and after stirring uniformly, it was placed in a 65℃ water bath for stirring reaction for 8h. After the reaction was completed, the pH was adjusted to neutral with 0.1mol / L dilute hydrochloric acid solution, and the pretreated paper pulp was washed with deionized water until there was no Cl - ion in the filtrate detected by silver nitrate solution; the washed paper pulp fibers were diluted with deionized water to a solid content of 0.5% mass fraction, and then a high-pressure homogenizer was used to homogenize at a pressure of 50MPa for 3 cycles to obtain uniform and transparent quaternary amine cellulose nanofiber water dispersion.

[0044] Carboxymethyl cellulose and hydroxyethyl cellulose were diluted with water and introduced into a high-pressure homogenizer for homogenization treatment, and then freeze-dried to obtain carboxymethyl cellulose nanofiber and hydroxyethyl cellulose nanofiber.

[0045] Calculation of the potassium permanganate loading of the porous material: the porous material is immersed in a saturated potassium permanganate solution, and the remaining saturated potassium permanganate solution is collected after filtration, and the potassium permanganate loading of the porous material is calculated by the difference.

[0046] Test of the ethylene removal capacity: the prepared slurry is coated on the surface of A4 paper, dried, and then placed in a container filled with a certain concentration of ethylene for adsorption. The ethylene content before and after adsorption is analyzed by a gas chromatograph, and the amount of ethylene removed per gram of potassium permanganate (ml) is calculated.

[0047] Example 1

[0048] An ethylene adsorption coating slurry for fruit and vegetable preservation, comprising a quaternary aminated cellulose nanofiber suspension and an ethylene adsorbent: potassium permanganate-loaded zeolite powder.

[0049] The preparation method of the ethylene adsorption coating slurry is as follows:

[0050] (1) 50 g of zeolite powder is immersed in a saturated potassium permanganate solution for 3 h, filtered, and dried at 60°C for 2 h to obtain 54.6 g of ethylene adsorbent, and 50 g of zeolite powder contains 4.6 g of potassium permanganate;

[0051] (2) The quaternary aminated cellulose nanofiber water suspension prepared above with a solid content of 0.5% mass fraction is diluted to a mass percentage concentration of 0.1%;

[0052] (3) 0.59 g of ethylene adsorbent is mixed with 49.41 g of quaternary aminated cellulose nanofiber suspension, high-speed dispersed for 10 min, and stirred uniformly to obtain an ethylene adsorption coating slurry.

[0053] 25 g of the slurry prepared in Example 1 is coated on the surface of A4 paper, dried, and then placed in a container filled with a certain concentration of ethylene for adsorption. After 48 h, the gas is taken with a syringe, and the ethylene content before and after adsorption is analyzed by a gas chromatograph. The removal amount of ethylene by the potassium permanganate-loaded zeolite powder / quaternary aminated cellulose nanofiber coating prepared in Example 1 is calculated to be 4.21 ml / g.

[0054] Example 2

[0055] An ethylene adsorption coating slurry for fruit and vegetable preservation, comprising a quaternary aminated cellulose nanofiber suspension and an ethylene adsorbent: potassium permanganate-loaded activated carbon.

[0056] The preparation method of the ethylene adsorption coating slurry is as follows:

[0057] (1) 50 g of activated carbon was soaked in a saturated solution of potassium permanganate for 190 min, filtered, and dried at 60°C for 2 h to obtain 54.6 g of ethylene absorbent, and 50 g of activated carbon contained 4.6 g of potassium permanganate;

[0058] (2) The prepared quaternary aminated cellulose nanofiber aqueous suspension with a solid content of 0.5% by mass was diluted to a mass percentage concentration of 0.1%;

[0059] (3) 0.59 g of ethylene absorbent was mixed with 49.41 g of quaternary aminated cellulose nanofiber suspension, and stirred uniformly to obtain an ethylene adsorption coating slurry.

[0060] 25 g of the slurry prepared in Example 2 was coated on the surface of A4 paper, dried, and placed in a container filled with ethylene for adsorption. After 48 h, the gas was taken with a syringe, and the ethylene content before and after adsorption was analyzed using a gas chromatograph. It was calculated that the ethylene removal amount of the activated carbon / quaternary aminated cellulose nanofiber coating loaded with potassium permanganate prepared in Example 2 was 2.52 ml / g.

[0061] Example 3

[0062] An ethylene adsorption coating slurry applied to fruit and vegetable preservation, comprising quaternary aminated cellulose nanofiber suspension and ethylene adsorbent: sepiolite loaded with potassium permanganate.

[0063] The preparation method of the ethylene adsorption coating slurry is as follows:

[0064] (1) 50 g of sepiolite was soaked in a saturated solution of potassium permanganate for 210 min, filtered, and dried at 60°C for 2 h to obtain 54.6 g of ethylene absorbent, and 50 g of sepiolite contained 4.6 g of potassium permanganate;

[0065] (2) The prepared quaternary aminated cellulose nanofiber aqueous suspension with a solid content of 0.5% by mass was diluted to a mass percentage concentration of 0.1%;

[0066] (3) 0.59 g of ethylene absorbent was mixed with 49.41 g of quaternary aminated cellulose nanofiber suspension, and stirred uniformly to obtain an ethylene adsorption coating slurry.

[0067] 25 g of the slurry prepared in Example 3 was coated on the surface of A4 paper, dried, and placed in a container filled with ethylene for adsorption. After 48 h, the gas was taken with a syringe, and the ethylene content before and after adsorption was analyzed using a gas chromatograph. It was calculated that the ethylene removal amount of the sepiolite / quaternary aminated cellulose nanofiber coating loaded with potassium permanganate prepared in Example 3 was 3.22 ml / g.

[0068] Example 4

[0069] An ethylene adsorption coating slurry applied to fruit and vegetable preservation, comprising a quaternary ammonium cellulose nanofiber suspension and an ethylene adsorbent: potassium permanganate loaded zeolite powder.

[0070] The preparation method of the ethylene adsorption coating slurry is:

[0071] (1) 50g of zeolite powder is soaked in a saturated potassium permanganate solution for 1.5h, filtered, and dried at 60℃ for 2h to obtain 52.5g of ethylene adsorbent, and 50g of zeolite powder contains 2.5g of potassium permanganate;

[0072] (2) The prepared quaternary ammonium cellulose nanofiber water suspension with a solid content of 0.5% mass fraction is diluted to a mass percentage concentration of 0.1%;

[0073] (3) 1.05g of ethylene adsorbent is mixed with 48.95g of quaternary ammonium cellulose nanofiber suspension, and stirred uniformly to obtain an ethylene adsorption coating slurry.

[0074] 25g of the slurry prepared in Example 4 is coated on the surface of A4 paper, dried, and placed in a container filled with ethylene for adsorption. After 48h, the gas is taken with a syringe, and the ethylene content before and after adsorption is analyzed using a gas chromatograph. The calculated removal amount of ethylene by the potassium permanganate loaded zeolite powder / quaternary ammonium cellulose nanofiber coating prepared in Example 4 is 3.35ml / g.

[0075] Example 5

[0076] An ethylene adsorption coating slurry applied to fruit and vegetable preservation, comprising a quaternary ammonium cellulose nanofiber suspension and an ethylene adsorbent: potassium permanganate loaded zeolite powder.

[0077] The preparation method of the ethylene adsorption coating slurry is:

[0078] (1) 50g of zeolite powder is soaked in a saturated potassium permanganate solution for 2.5h, filtered, and dried at 60℃ for 2h to obtain 54.0g of ethylene adsorbent, and 50g of zeolite powder contains 4.0g of potassium permanganate;

[0079] (2) The prepared quaternary ammonium cellulose nanofiber water suspension with a solid content of 0.5% mass fraction is diluted to a mass percentage concentration of 0.1%;

[0080] (3) 0.675g of ethylene adsorbent is mixed with 49.325g of quaternary ammonium cellulose nanofiber suspension, and stirred uniformly to obtain an ethylene adsorption coating slurry.

[0081] Take the 25g slurry prepared in Example 5 coated on the surface of A4 paper, dried and placed in a container filled with ethylene for adsorption. After 48h, the gas was taken with a syringe and the ethylene content before and after adsorption was analyzed using a gas chromatograph. The calculated removal amount of ethylene by the potassium permanganate-loaded zeolite powder / quaternary aminofiber nanofiber coating prepared in Example 5 was 4.05ml / g.

[0082] Example 6

[0083] An ethylene adsorption coating slurry for fruit and vegetable preservation, comprising a quaternary aminofiber nanofiber suspension and an ethylene adsorbent: potassium permanganate-loaded zeolite powder.

[0084] The preparation method of the ethylene adsorption coating slurry is:

[0085] (1) 50g of zeolite powder was soaked in a saturated potassium permanganate solution for 3.5h, filtered and dried at 60℃ for 2h to obtain 55.0g of ethylene adsorbent, and 50g of zeolite powder contained 5.0g of potassium permanganate;

[0086] (2) The quaternary aminofiber nanofiber water suspension prepared above with a solid content of 0.5% mass fraction was diluted to a mass percentage concentration of 0.1%;

[0087] (3) 0.55g of ethylene adsorbent was mixed with 49.45g of quaternary aminofiber nanofiber suspension, and stirred uniformly to obtain an ethylene adsorption coating slurry.

[0088] Take the 25g slurry prepared in Example 6 coated on the surface of A4 paper, dried and placed in a container filled with ethylene for adsorption. After 48h, the gas was taken with a syringe and the ethylene content before and after adsorption was analyzed using a gas chromatograph. The calculated removal amount of ethylene by the potassium permanganate-loaded zeolite powder / quaternary aminofiber nanofiber coating prepared in Example 6 was 4.16ml / g.

[0089] Example 7

[0090] An ethylene adsorption coating slurry for fruit and vegetable preservation, comprising a quaternary aminofiber nanofiber suspension and an ethylene adsorbent: potassium permanganate-loaded zeolite powder.

[0091] The preparation method of the ethylene adsorption coating slurry is:

[0092] (1) 50g of zeolite powder was soaked in a saturated potassium permanganate solution for 4h, filtered and dried at 60℃ for 2h to obtain 55.4g of ethylene adsorbent, and 50g of zeolite powder contained 5.4g of potassium permanganate;

[0093] (2) Dilute the prepared quaternary amine cellulose nanofiber water suspension with a solid content of 0.5% by mass fraction to a mass percentage concentration of 0.1%;

[0094] (3) Mix 0.51 g of ethylene absorber with 49.49 g of quaternary amine cellulose nanofiber suspension, stir uniformly, and obtain an ethylene adsorption coating slurry.

[0095] Take 25 g of the slurry prepared in Example 7 and coat it on the surface of an A4 paper. After drying, place it in a container filled with ethylene and perform adsorption for 48 h. After that, use a syringe to take the gas and use a gas chromatograph to analyze the ethylene content before and after adsorption. It is calculated that the ethylene removal amount of the potassium permanganate loaded zeolite powder / quaternary amine cellulose nanofiber coating prepared in Example 7 is 4.07 ml / g.

[0096] Example 8

[0097] An ethylene adsorption coating slurry applied to fruit and vegetable preservation, comprising a TEMPO oxidized cellulose nanofiber suspension and an ethylene absorber: potassium permanganate loaded zeolite powder.

[0098] The preparation method of the ethylene adsorption coating slurry is as follows:

[0099] (1) Soak 50 g of zeolite powder in a saturated potassium permanganate solution for 3 h, filter, and dry at 50°C for 3 h to obtain 54.6 g of ethylene absorber. The 50 g of zeolite powder contains 4.6 g of potassium permanganate;

[0100] (2) Dilute the purchased TEMPO oxidized cellulose nanofiber suspension to a mass percentage concentration of 0.1%;

[0101] (3) Mix 0.59 g of ethylene absorber with 49.41 g of TEMPO oxidized cellulose nanofiber suspension, stir uniformly, and obtain an ethylene adsorption coating slurry.

[0102] Take 25 g of the slurry prepared in Example 8 and coat it on the surface of an A4 paper. After drying, place it in a container filled with ethylene and perform adsorption for 48 h. After that, use a syringe to take the gas and use a gas chromatograph to analyze the ethylene content before and after adsorption. It is calculated that the ethylene removal amount of the potassium permanganate loaded zeolite powder / TEMPO oxidized cellulose nanofiber coating prepared in Example 8 is 4.17 ml / g.

[0103] Example 9

[0104] An ethylene adsorption coating slurry applied to fruit and vegetable preservation, comprising a quaternary amine cellulose nanofiber / TEMPO oxidized cellulose nanofiber suspension and an ethylene absorber: potassium permanganate loaded zeolite powder.

[0105] The preparation method of the ethylene adsorption coating slurry is as follows:

[0106] (1) 50 g of zeolite powder was soaked in a saturated potassium permanganate solution for 3 h, filtered, and dried at 65°C for 2.5 h to obtain 54.6 g of ethylene absorbent, and 50 g of zeolite powder contained 4.6 g of potassium permanganate;

[0107] (2) The quaternary aminated cellulose nanofiber and the purchased TEMPO-oxidized cellulose nanofiber prepared above were both diluted to a mass percentage concentration of 0.1%, and then mixed in equal amounts to obtain a quaternary aminated cellulose nanofiber / TEMPO-oxidized cellulose nanofiber suspension;

[0108] (3) 0.59 g of the ethylene absorbent was mixed with 49.41 g of the quaternary aminated cellulose nanofiber / TEMPO-oxidized cellulose nanofiber suspension, and stirred uniformly to obtain an ethylene adsorption coating slurry.

[0109] 25 g of the slurry prepared in Example 9 was coated on the surface of an A4 paper, dried, and then placed in a container filled with ethylene for adsorption. After 48 h, the gas was taken out with a syringe, and the ethylene content before and after adsorption was analyzed using a gas chromatograph. It was calculated that the removal amount of ethylene by the zeolite powder loaded with potassium permanganate / quaternary aminated cellulose nanofiber / TEMPO-oxidized cellulose nanofiber coating prepared in Example 9 was 4.35 ml / g.

[0110] Comparative Example 1

[0111] 50 g of zeolite powder was soaked in a saturated potassium permanganate solution for 3 h, filtered, and dried at 60°C for 2 h to obtain 54.6 g of ethylene absorbent, and 50 g of zeolite powder contained 4.6 g of potassium permanganate;

[0112] 0.59 g of the zeolite powder loaded with potassium permanganate was placed in a sealed container, filled with ethylene, and left for 48 h. After that, the gas was taken out with a syringe, and the ethylene content before and after adsorption was analyzed using a gas chromatograph. It was calculated that the removal amount of ethylene by the zeolite powder loaded with potassium permanganate prepared in Comparative Example 1 was 1.12 ml / g.

[0113] Comparative Example 2

[0114] 50 g of activated carbon was soaked in a saturated potassium permanganate solution for 190 min, filtered, and dried at 60°C for 2 h to obtain 54.6 g of ethylene absorbent, and 50 g of activated carbon contained 4.6 g of potassium permanganate;

[0115] 0.59 g of the activated carbon loaded with potassium permanganate was placed in a sealed container, filled with ethylene, and left for 48 h. After that, the gas was taken out with a syringe, and the ethylene content before and after adsorption was analyzed using a gas chromatograph. It was calculated that the removal amount of ethylene by the zeolite powder loaded with potassium permanganate prepared in Comparative Example 2 was 0.76 ml / g.

[0116] Comparative Example 3

[0117] The ethylene adsorption coating slurry prepared in Comparative Example 3 comprises a corn starch suspension and an ethylene adsorbent: potassium permanganate-loaded zeolite powder.

[0118] The preparation method of the ethylene adsorption coating slurry is as follows:

[0119] (1) 50 g of zeolite powder was soaked in a saturated potassium permanganate solution for 3 h, and 54.6 g of an ethylene adsorbent was obtained after filtration and drying at 60°C for 2 h, with 50 g of zeolite powder containing 4.6 g of potassium permanganate;

[0120] (2) 11 g of corn starch was dispersed in 39 g of water to obtain a corn starch suspension;

[0121] (3) 0.59 g of the ethylene adsorbent was mixed with 49.41 g of the corn starch suspension, and the mixture was stirred uniformly to obtain an ethylene adsorption coating slurry.

[0122] 25 g of the slurry prepared in Comparative Example 3 was coated on the surface of an A4 paper, dried, and then placed in a container filled with ethylene for adsorption. After 48 h, the gas was taken out with a syringe, and the ethylene content before and after adsorption was analyzed using a gas chromatograph. It was calculated that the ethylene removal amount of the potassium permanganate-loaded zeolite powder / corn starch coating prepared in Comparative Example 3 was 2.92 ml / g.

[0123] Comparative Example 4

[0124] Potassium permanganate-loaded activated carbon was mixed with a corn starch suspension

[0125] The ethylene adsorption coating slurry prepared in Comparative Example 4 comprises a corn starch suspension and an ethylene adsorbent: potassium permanganate-loaded activated carbon.

[0126] The preparation method of the ethylene adsorption coating slurry is as follows:

[0127] (1) 50 g of activated carbon was soaked in a saturated potassium permanganate solution for 190 min, and 54.6 g of an ethylene adsorbent was obtained after filtration and drying at 60°C for 2 h, with 50 g of activated carbon containing 4.6 g of potassium permanganate;

[0128] (2) 11 g of corn starch was dispersed in 39 g of water to obtain a corn starch suspension;

[0129] (3) 0.59 g of the ethylene adsorbent was mixed with 49.41 g of the corn starch suspension, and the mixture was stirred uniformly to obtain an ethylene adsorption coating slurry.

[0130] 25g slurry prepared in Comparative Example 4 was coated on the surface of A4 paper, dried and placed in a container filled with ethylene for adsorption. After 48h, the gas was taken with a syringe and the ethylene content before and after adsorption was analyzed using a gas chromatograph. The amount of ethylene removed by the coating of zeolite powder loaded with potassium permanganate / corn starch prepared in Comparative Example 4 was calculated to be 1.62ml / g.

[0131] Comparative Example 5

[0132] The ethylene adsorption coating slurry prepared in Comparative Example 5 included a suspension of carboxymethyl cellulose nanofiber and an ethylene adsorbent: zeolite powder loaded with potassium permanganate.

[0133] The preparation method of the ethylene adsorption coating slurry was as follows:

[0134] (1) 50g of zeolite powder was soaked in a saturated solution of potassium permanganate for 3h, filtered and dried at 60°C for 2h to obtain 54.6g of an ethylene adsorbent, and 50g of zeolite powder contained 4.6g of potassium permanganate;

[0135] (2) The purchased carboxymethyl cellulose nanofiber was diluted to a mass percentage concentration of 0.1%;

[0136] (3) 0.59g of the ethylene adsorbent was mixed with 49.41g of the suspension of carboxymethyl cellulose nanofiber, and stirred uniformly to obtain an ethylene adsorption coating slurry.

[0137] 25g of the slurry prepared in Comparative Example 5 was coated on the surface of A4 paper, dried and placed in a container filled with ethylene for adsorption. After 48h, the gas was taken with a syringe and the ethylene content before and after adsorption was analyzed using a gas chromatograph. The amount of ethylene removed by the coating of zeolite powder loaded with potassium permanganate / carboxymethyl cellulose nanofiber prepared in Comparative Example 5 was calculated to be 3.24ml / g.

[0138] Comparative Example 6

[0139] The ethylene adsorption coating slurry prepared in Comparative Example 6 included a suspension of hydroxyethyl cellulose nanofiber and an ethylene adsorbent: zeolite powder loaded with potassium permanganate.

[0140] The preparation method of the ethylene adsorption coating slurry was as follows:

[0141] (1) 50g of zeolite powder was soaked in a saturated solution of potassium permanganate for 3h, filtered and dried at 60°C for 2h to obtain 54.6g of an ethylene adsorbent, and 50g of zeolite powder contained 4.6g of potassium permanganate;

[0142] (2) The purchased hydroxyethyl cellulose nanofiber was diluted to a mass percentage concentration of 0.1%;

[0143] (3) 0.59 g ethylene absorbent was mixed with 49.41 g hydroxyethyl cellulose nanofiber suspension, stirred uniformly to obtain an ethylene adsorption coating slurry.

[0144] 25 g slurry prepared in Comparative Example 6 was coated on the surface of A4 paper, dried, and placed in a container filled with ethylene for adsorption. After 48 h, the gas was taken with a syringe, and the ethylene content before and after adsorption was analyzed using a gas chromatograph. It was calculated that the amount of ethylene removed by the zeolite powder / potassium permanganate-hydroxyethyl cellulose nanofiber coating prepared in Comparative Example 6 was 3.06 ml / g.

[0145] As can be seen from the above examples and comparative examples, zeolite powder, activated carbon, and sepiolite loaded with potassium permanganate as ethylene absorbent all have good effects on ethylene absorption, and zeolite powder is more preferred for better absorption effect. The soaking time of the porous material in the saturated potassium permanganate solution should be controlled within a reasonable range to control the loading amount of potassium permanganate in the porous material and ensure efficient absorption of the ethylene absorbent. The quaternary aminated cellulose nanofiber and / or TEMPO-oxidized cellulose nanofiber as a film former effectively increases the contact area between potassium permanganate and ethylene compared to corn starch and other types of cellulose nanofiber, thereby improving the absorption effect of ethylene.

[0146] As can be seen from Examples 1-3, zeolite powder, activated carbon, and sepiolite loaded with potassium permanganate as ethylene absorbent all have good effects on ethylene absorption, and zeolite powder is more preferred for better absorption effect. As can be seen from Examples 1, 4-7, when the loading amount of potassium permanganate in the porous material is too small, the ethylene adsorption effect is not good, and when the loading amount is too large, the ethylene adsorption amount is reduced. The loading amount of potassium permanganate in the porous material is controlled by the soaking time. As can be seen from the comparison of Example 1, Examples 8-9, when the cellulose nanofiber suspension is a composite suspension of quaternary aminated cellulose nanofiber and TEMPO-oxidized cellulose nanofiber, the coating has better ethylene adsorption efficiency. As can be seen from the comparison of Example 1, Comparative Examples 1-5, the quaternary aminated cellulose nanofiber and / or TEMPO-oxidized cellulose nanofiber as a film former effectively increases the contact area between potassium permanganate and ethylene compared to not adding a film former, corn starch, and other types of cellulose nanofiber, thereby improving the absorption effect of ethylene.

[0147] Aspects, embodiments, features of the present application should be considered illustrative in all aspects and do not limit the present application, and the scope of the present application is defined only by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed application.

[0148] It should be noted that the embodiments described herein are merely illustrative of the present application and should not be construed as limiting the scope of the present application. Those skilled in the art can make various modifications or additions to the embodiments described herein or adopt similar ways to replace them without departing from the spirit of the present application. It is not necessary or possible to describe all the embodiments herein. Any obvious changes or variations derived from the spirit of the present application are still within the scope of the present application, and any additional limitations are contrary to the spirit of the present application.

Claims

1. An ethylene adsorbing coating paste for use in the preservation of fruits and vegetables, characterized by, The ethylene adsorption coating slurry comprises a cellulose nanofiber suspension and a porous material loaded with potassium permanganate. The cellulose nanofiber suspension is formed by dispersing cellulose nanofibers in water, and the mass percentage concentration of the cellulose nanofiber suspension is 0.05-0.30%. The cellulose nanofibers are a mixture of TEMPO-oxidized cellulose nanofibers and quaternized cellulose nanofibers.

2. The ethylene adsorbing coating paste for preserving fruits and vegetables according to claim 1, characterized in that, In the ethylene adsorption coating slurry, the mass percentage concentration of potassium permanganate is 0.05-0.50%.

3. The ethylene adsorbing coating paste for preserving fruits and vegetables according to claim 1, characterized in that, 1-20 g of potassium permanganate is loaded per 100 g of the porous material.

4. The ethylene adsorption coating paste for preserving fruits and vegetables according to claim 1 or 3, characterized in that, The porous material is one or more of zeolite powder, silicon oxide, sepiolite, activated carbon, alumina, and diatomite.

5. The ethylene adsorbing coating paste for preserving fruits and vegetables according to claim 1, characterized in that, The method for preparing the porous material loaded with potassium permanganate comprises the following steps:

6. A method for preparing an ethylene adsorbing coating paste for the preservation of fruits and vegetables as claimed in claim 1, characterized in that, The porous material is soaked in a saturated potassium permanganate solution, filtered, and dried to obtain an ethylene adsorbent. The method comprises the following steps: The porous material is soaked in a saturated potassium permanganate solution, filtered, and dried to obtain an ethylene adsorbent. A cellulose nanofiber suspension with a suitable concentration is prepared.

7. Use of an ethylene adsorbing coating slurry for the preservation of fruits and vegetables, characterized in that, The ethylene adsorbent is mixed with the cellulose nanofiber suspension, and stirred uniformly to obtain an ethylene adsorption coating slurry. The ethylene adsorption coating slurry of claim 1 or the ethylene adsorption coating slurry prepared by the method of claim 6 is coated on the inner layer of fruit and vegetable outer packaging or preservative paper, and dried to obtain fruit and vegetable outer packaging or preservative paper with an ethylene adsorption coating.