CN1559238A - Fruit and vegetable fresh-keeping sterilizer and its preparation method and application - Google Patents

Abstract

An antistaling bactericide for fruit and vegetable is prepared from water, alcohol chosen from ethanol, propanetriol, ethanediol and isopropanol, visual light catalyst (MCM-41 or ALMCM-41 carried TiO2 or ultraviolet catalyst chosen from TiO2, zinc oxide and magnesium oxide, Ag nanoparticles, sodium hexametaphosphate, and sodium silicate.

Description

Fruit and vegetable fresh-keeping sterilizer and its preparation method and application

Technical field: The present invention relates to a fruit and vegetable fresh-keeping sterilizer and its preparation method and application.

Background technology: temperature, humidity, gas and anti-corrosion are the four elements of the modern fresh-keeping technology of fruits and vegetables. To solve such problems, temperature control usually adopts mechanical refrigeration, anticorrosion mainly uses chemical agents, and humidity and gas control mainly adopts two methods: spontaneous air conditioning and mechanical air conditioning. These methods have their own advantages and disadvantages: the large-scale investment and high energy consumption required for low-temperature air-conditioning fresh-keeping; and ordinary fresh-keeping fungicides may have residual poisons, especially fresh-keeping fungicides with organic matter as the main component. During the storage process, fruits and vegetables will release ethylene or carbon dioxide gas. These gases can cause physiological changes in fruits and vegetables, and promote post-ripening, aging and even rotten deterioration of fruits and vegetables.

In order to eliminate the influence of ethylene and carbon dioxide gas emitted by fruits and vegetables on fruits and vegetables, the currently used preservatives are mainly adsorption type based on activated carbon and oxidative decomposition type based on potassium permanganate. Although the former has a high removal rate, it will fail after adsorption saturation, and there is even a risk of desorption; the latter has the disadvantages of slow removal speed and insignificant fresh-keeping effect. Using fresh-keeping coatings to regulate the respiration and water transpiration of fruits and vegetables, inhibit vigorous physiological metabolic changes, reduce nutrient loss, and achieve the purpose of long-term storage and quality maintenance. Therefore, fresh-keeping coating is a better method of modified atmosphere fresh-keeping. It is worth mentioning that CN01129896.0, the method for making nano-photocatalyst film and the fresh-keeping device for fruits, vegetables and flowers achieves the purpose of fresh-keeping by decomposing ethylene into carbon dioxide and water under ultraviolet rays through the nano-coating of the equipment. Photocatalyst absorbs sunlight and ultraviolet rays from fluorescent lamps to excite oxygen and water molecules in the air to produce negative oxygen and hydroxyl radicals with super oxidizing ability, destroying the cell membrane of bacteria, causing the loss of cytoplasm, and inhibiting the activity of viruses. The role of removing bacteria in the air.

Fruits and vegetables are affected by surface soil and microorganisms in the air during the growth process. There will be a large number of harmful bacteria on the surface of fruits and vegetables, which will multiply in large numbers during storage, causing the fruits and vegetables to rot and deteriorate. Therefore, in the fresh-keeping treatment of fruits and vegetables, sterilization treatment should be carried out first. Most of the fungicides currently on the market have certain toxicity, and their residues are harmful to human health. In practice, various methods such as coating preservation method, chemical storage method, and biological antiseptic method are used to prevent stored fruits and vegetables from being infected by mold and rot, or to inhibit the metabolism of fruits and vegetables, prevent aging, and prolong the storage period.

From the perspective of the choice of preservatives, thiophanate and carbendazim were the two fungicides most used in my country in the past. Their outstanding features are high efficiency and systemic effect. The main disadvantage is that due to the rapid emergence of resistant bacteria, the drug The effect is reduced, and the systemic effect leads to high residues. If this preservative is used for thin-skinned fruits such as apples and pears, the residual heavy pesticide smell becomes its obvious shortcoming. CN95108788.6 and CN01136473.4 disclose fruit and vegetable fresh-keeping coatings, fruit and vegetable fresh-keeping agents and their application techniques, both of which use organic preservatives. CN00127606.9 is an antibacterial and mildew-proof fresh-keeping film and its manufacturing method. The surface and micropores are covered with nano-scale silver silicate clay particles, which do not have the performance of decomposing ethylene.

Summary of the invention: The present invention provides a fruit and vegetable fresh-keeping sterilizer and its production method and application. It combines the function of decomposing ethylene by photocatalysis and the bactericidal function of nano-element silver for fruit and vegetable preservation. It does not contain preservatives and can not only kill Mold, and can also kill bacteria. Since this product contains inorganic fungicides, it will not cause peculiar smell to the fruit. In addition to sterilization, it also has the function of decomposing ethylene. Compared with the existing fresh-keeping paper, the composition and efficacy are different. Moreover, it does not contain chlorine; the production process is simple, the raw materials are cheap and easy to obtain, safe and non-toxic, and the fresh-keeping effect is good.

The present invention is realized through the following technical measures:

A fresh-keeping and sterilizing agent for fruits and vegetables, characterized in that it is a neutral aqueous solution containing nano-metals, photocatalysts, dispersants and water with a pH value of 6-7, and contains the following ingredients by weight percentage:

Nano metal 0.10～2.2

Photocatalyst 1.0～25.0

Dispersant 0.50～12.0

Water 80～98

The above-mentioned dispersant can be ethylene glycol, sodium hexametaphosphate, sodium silicate, ethanol, wherein ethylene glycol can be used alone, and other several kinds need to be used together.

The above-mentioned nanometer metal is 5-60nm elemental silver, and the photocatalyst includes visible light catalyst or ultraviolet photocatalyst loaded with titanium dioxide and based on MCM-41 or AlMCM-41, which can be 10-30nm titanium dioxide, 5-30nm zinc oxide, 2-30nm At least two of magnesium oxide.

The invention relates to a production method of a fruit and vegetable fresh-keeping sterilizing agent. According to the above-mentioned proportions, various raw material powders are mixed, added into water, stirred evenly, beaten, and then coated on various substrates.

The fruit and vegetable fresh-keeping sterilizing agent can be used as a carrier at normal temperature, brushed, sprayed or soaked on the paper, and after drying, it is ideal for fruit fresh-keeping and storage. The fresh-keeping paper can also be processed into packaging bags and liner paper in boxes. It can be used for the controlled atmosphere preservation of fresh fruits, vegetables and flowers, etc. This fresh-keeping coating is suitable for storing various fruits and vegetables such as pears, mangoes, lychees, apples, tomatoes, bananas, peaches, green peppers, and pineapples.

In particular, the photocatalytic decomposition of ethylene and bactericidal efficiency of ordinary ultraviolet photocatalysts will be greatly reduced due to the lack of ultraviolet light irradiation at night and after the lights are turned off. The fruit and vegetable fresh-keeping sterilizing agent provided by the present invention adopts a high-efficiency photocatalyst, and has higher activity under visible light, so it can be sterilized even without ultraviolet rays.

The fresh-keeping material for fruits and vegetables provided by the invention does not require large investment in equipment and is easy to use. It can be used as a fresh-keeping coating, directly applied to the surface of fruits and vegetables by smearing, spraying, etc., and forms a thin transparent film after air-drying to enhance the protective effect of the fruit and vegetable skin; properly block the openings, inhibit respiration, and reduce nutrition Consumption; Inhibit water distribution, prevent shrinkage and wilting; Inhibit microbial invasion, prevent spoilage. You can also put the powdered preservative into a breathable cloth bag and seal it for later use.

Detailed ways:

Example 1.

a. According to the method disclosed in CN1431051, a visible light catalyst loaded with titanium dioxide and based on MCM-41 or AlMCM-41 was prepared.

b. Preparation of nano-silver sol: 16g of silver nitrate dissolved in 100kg of water was added to the aqueous solution of sodium borohydride dissolved in 100kg of water by 8g of sodium borohydride.

c. Add 5 g of the visible light catalyst prepared in step a to a solution of 1800 g of water and 180 g of ethylene glycol, stir vigorously, then add 100 g of nano-silver sol prepared in step b, and stir fully to obtain the fruit and vegetable fresh-keeping sterilizer.

Example 2.

3g of the photocatalyst prepared in step a of Example 1 was added to the solution obtained by 1500g of water, 15g of sodium hexametaphosphate, 5g of sodium silicate and 50g of 99% ethanol, stirred vigorously, and then added 100g of the photocatalyst prepared in step b of Example 1. Silver sol, fully stirred to get fruit and vegetable fresh-keeping sterilizer.

Example 3.

The ultraviolet light photocatalyst of 8g titanium dioxide (12nm) and 2g zinc oxide (20nm) is added in the solution of 2000g water and 18g ethylene glycol and 30g ethanol, vigorously stirs, then adds the nano-silver sol made in step b in 120g embodiment 1, fully Stir to obtain the fruit and vegetable fresh-keeping sterilizer.

Example 4.

The ultraviolet photocatalyst of 6g titanium dioxide (12nm) and 3g magnesium oxide (16nm) is added in the solution of 1500g water and 13g ethylene glycol and 20g ethanol, vigorously stirs, then adds the nano-silver sol made in step b in 80g embodiment 1, fully Stir to obtain the fruit and vegetable fresh-keeping sterilizer.

Example 5.

Add the ultraviolet photocatalyst of 10g titanium dioxide (12nm), 2g zinc oxide (20nm) and 1g magnesium oxide (16nm) in the solution of 2200g water and 20g ethylene glycol and 16g ethanol, vigorously stir, then add step b in 60g embodiment 1 The prepared nano-silver sol is fully stirred to obtain a fruit and vegetable fresh-keeping sterilizer. Applications:

1. Spray 20g of the prepared fruit and vegetable fresh-keeping sterilizer on a ^1m2 wrapping paper to obtain wrapping paper that can be used for fresh-keeping.

2. Spray 20g of the prepared fruit and vegetable fresh-keeping sterilizer directly on the fruit that has been packed in ordinary wrapping paper, or directly spray on the fruit and vegetable, or spray it in the packaging carton of the fruit and vegetable.

Claims (6)

1. preserving fruit and vegetable utilizing bactericidal agent is characterized in that: it is that the pH value that contains nano metal, photochemical catalyst, dispersant and water is 6～7 neutral aqueous solution.

2. by the described bactericidal agent of claim 1, it is characterized in that containing by weight percentage following composition:

Nano metal 0.10～2.2

Photochemical catalyst 1.0～25.0

Dispersant 0.50～12.0

Water 80～98

3. bactericidal agent according to claim 1 is characterized in that: dispersant can be ethylene glycol, sodium hexametaphosphate, sodium silicate, ethanol, and wherein ethylene glycol can use separately, and other several need use jointly.

4. bactericidal agent according to claim 1, it is characterized in that: nano metal is 5～60nm simple substance silver, photochemical catalyst comprises that supported titanium dioxide is the visible light catalyst or the ultraviolet light catalyst of matrix with MCM-41 or AlMCM-41, can be at least two kinds in 10～30nm titanium dioxide, 5～30nm zinc oxide, the 2～30nm magnesia.

5. a preserving fruit and vegetable utilizing bactericidal agent preparation method is made: in the described ratio of claim 2, each raw meal is mixed, add in the entry, stir, pull an oar, be coated on then on the various base materials according to the following steps.

6. fruit and vegetable antistaling disinfectant according to claim 1, it is characterized in that can be at normal temperatures, with paper as carrier, adopt brushing, spray or be soaked on the paper, after drying, as fruit fresh-keeping and storage effect ideal, this tin foil also can be processed into packing paper use in packaging bag, the case, can be used for the controlled atmosphere of fresh fruit, vegetables, fresh flower etc., this antistaling coating is suitable for preserving pears, mango, lichee, apple, tomato, fragrant Jiao, peach, green pepper, the multiple fruits and vegetables of pineapple.