Application of ozone in storage and preservation o

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The application of ozone in the storage and preservation of fruits and vegetables

the application of ozone in the storage of vegetables and fruits can not only kill or inhibit the growth of mold and prevent decay, but also prevent aging and preservation. Its mechanism is that ozone can oxidize and decompose the ripening agent --- ethylene gas C2H4, which is decomposed by respiration of fruits and vegetables. The reaction process is as follows: the by-products of ethylene reaction can inhibit microorganisms such as mold. Ozone plays a role in sterilization and mold prevention and rapid decomposition of ethylene, slows down new aging, and delays post ripening, aging and decay. The use of ozone should be combined with packaging, refrigeration, air conditioning and other means to better improve the fresh-keeping effect

ozone technology has been widely used in storage and preservation abroad, and experts in China have conducted a variety of experiments to study the application of ozone in the preservation industry. Mold is the biggest enemy of the fresh-keeping industry and the main cause of storage spoilage. Ozone has the advantages of strong bactericidal power, wide bactericidal spectrum, self decomposition without residual pollution, and high efficiency in killing mold. On the other hand, ozone gas can quickly decompose the ethylene gas emitted by the respiration of fruits and vegetables. Ethylene is a ripening agent, which will enhance the respiration and accelerate to 4 Product training and maintenance process. The decomposition of ethylene reduces metabolism and slows down the physiological aging process, thus realizing the fresh-keeping effect. The fresh-keeping time of fruits fresh-keeping by ozone is longer than that of fruits fresh-keeping in general cold storage. At the same time, ozone cylinders and breathing steel or composite materials can also remove the odor in the warehouse

I. overview of ozone application in storage and preservation industry

ozone has been used in storage and preservation abroad for nearly a century. The technology and application of food storage with O3 was first adopted in Japan, Germany and other countries. According to the kuprianoff report in 1953, ozone was used in meat refrigeration in Cologne, Germany, in 1909, which is the earliest example of ozone as a food preservative. In 1924, Hautman "ozone successfully prevented the growth of bacteria during cold storage" (p.724), "when the relative humidity is 88%-90%, eggs are stored, ozone prevented the formation of mold" (p.725). Hartman concluded that ozone "has many uses in refrigeration, with rapid changes and remarkable results" (p.725). At the end of the 1930s, 80% of the refrigerated egg warehouses in the United States were equipped with ozone generators

with the development and improvement of the manufacturing technology of ozone generator in China, ozone has been more and more widely used in the field of storage, preservation, disinfection and sterilization in China because of its good sterilization effect, no secondary pollution, convenient use and other advantages. The non reprocessability of thermosetting photosensitive polymers in many universities and research institutes will cause a lot of material waste and serious environmental impact. They are still testing their application methods in different fruits and food storage. The best way to keep some fruits and foods fresh is to combine wet and cold preservation with ozone technology

Second, the mechanism of Ozone Preservation

the application of ozone in the storage and preservation industry is mainly based on the following three aspects:

◇ killing microorganisms -- sterilization and disinfection

◇ oxidize and decompose all kinds of smelly inorganic or organic substances -- deodorize

◇ decompose and oxidize metabolic products, so as to inhibit metabolic process -- fresh keeping

1. Sterilization and disinfection effect of ozone

ozone has a strong sterilization ability, and ozone achieves the purpose of killing microorganisms by its strong oxidation effect. It reacts with many components in microbial cells, resulting in irreversible changes. It is generally believed that the cell membrane first acts on microorganisms, causing damage to membrane components, causing metabolic disorders and inhibiting their growth. Ozone continues to penetrate and destroy the tissue in the membrane until it is killed. The increase of humidity can improve the bactericidal power. Due to the thinning of microbial cell membrane under high humidity, its tissue is easy to be destroyed by ozone

the advantages of ozone sterilization are: the final product of ozone is oxygen, so it is pollution-free; There will be no residue on the storage, which has no impact on food; Low cost; With ultraviolet sterilization, its dorsal genitals have no effect, while ozone has a bactericidal effect on the whole space

2. Deodorization effect of ozone

the use of ozone deodorization is mainly due to its strong oxidation, which can effectively oxidize and decompose all kinds of odors generated in storage, so as to maintain the fresh air in the warehouse. The main components of the odor are ammonia, hydrogen sulfide, methyl mercaptan, dimethyl sulfur compounds, dimethyl disulfide, etc

3. Fresh keeping effect of ozone

ozone can keep fresh because it can slow down the metabolic process and delay post ripening and aging, which is achieved by decomposing ethylene gas by ozone

fruits and vegetables are still living after picking, and the respiratory process is accelerated during storage, so they gradually mature. The purpose of cooling and regulating qi is to reduce its respiratory effect. Fruits and vegetables will produce a large amount of ethylene at the stage of approaching maturity. It has the effect of accelerating maturity, which is called ripening agent. Its diffusion will also accelerate the maturation of other fruits and vegetables. Ozone can effectively control this process, quickly oxidize and decompose ethylene, and finally generate carbon dioxide and water. Ozone plays an important role in prolonging the storage period of fruits and vegetables

III. selection and application principles of ozone generator

generally in the storage and fresh-keeping industry, there is a large space for disinfection and fresh-keeping, so a large forced diffusion "open" ozone generator should be selected and installed above the warehouse for the diffusion of ozone. Storage fresh-keeping disinfection requires high concentration and large ozone consumption. Generally, 1000 cubic meters of space can be selected according to the specification of 10 ~ 15 grams/hour

the killing effect of ozone on microorganisms in the warehouse depends on the concentration of ozone, microbial species, treatment time, warehouse temperature and humidity, wall, ceiling, ground materials, etc

to disinfect the empty warehouse with ozone, the goods in the warehouse should be emptied and cleaned first, and the cushion board should be washed and dried. Under the condition of ozone concentration of 6 ~ 10ppm, disinfect for more than 2 hours, shut down the machine and seal the warehouse for 24 ~ 48 hours, and use ozone to disinfect the bacteria in the empty warehouse. The killing rate of bacteria is more than 90%, and the killing rate of mold is more than 80%

IV. application of ozone in the storage and fresh-keeping industry

1. Egg disinfection and fresh-keeping

when eggs are picked out from the henhouse, the surface of the eggshell carries a large number of bacteria and viruses, which may invade the egg body, destroy the egg quality, or infect bacteria due to contact with hands. For breeding eggs, it will affect the hatching rate and the quality of chicks. Although the cost of chemical fumigation and liquid medicine spray disinfection is very low, it may produce another kind of pollution. In the egg processing workshop, soaking and disinfecting eggs with ozone water can thoroughly kill all kinds of bacteria and viruses on their surface

install ozone sterilization, mildew prevention and fresh-keeping system in the egg storehouse to maintain a certain ozone concentration in the storehouse for a long time (shut down during centralized import and export). It can significantly reduce the number of microorganisms on the surface of the eggshell, which can not only meet the requirements of customers for egg hygiene, but also prolong the preservation time of eggs

for egg banks, higher relative humidity can reduce the evaporation of water in eggs and improve the hatching rate, but high humidity will promote the growth of mold. Ozone sterilization and fresh-keeping system can solve this problem

the ozone concentration in the egg bank is generally within the range of 0.5 ~ 1.5ppm, which should be determined according to the specific situation of passenger car manufacturers with six brands

2. Fresh keeping and storage of fruits

it can effectively solve the problems of decay, long hair, soft ripening and deterioration of fruits during storage. On the basis of the existing mechanical cold storage, applying Baorui ads series ozone fresh-keeping system and matching the humidification device of the cold storage can successfully solve a series of fruit storage and fresh-keeping problems. This design is especially suitable for grapes, peaches, winter jujubes, kiwifruit, citrus and other fruits that are prone to bacterial decay and soft ripening. There is no need for preservatives and bagging, which greatly reduces the workload of warehousing, eliminates the pollution and damage of sulfur dioxide and other chemicals to fruits, and relatively prolongs the fruit preservation and storage cycle

3. Mold prevention of other items

items that need to be stored in a humid enclosed space for a long time and are easy to mold, rot or deteriorate. If they are not sensitive to ozone and there is no ozone sensitive equipment in the storage facilities, ozone technology is suitable for mold prevention, sterilization and odor removal, and has an extremely significant effect. The ozone concentration can be set within the range of 0.3 ~ 1.0ppm

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