What is the importance of controlled atmosphere storage for the preservation of fruits and vegetables?

According to the 2013-2017 China Cold Chain Logistics Industry Market Research and Investment Forecast Analysis Report, the annual loss rate of fruits, vegetables and other agricultural products in China in the logistics links such as picking, transportation and storage is as high as 25% to 30%. Such huge loss is the key factor causing the high price of many fruits and vegetables products. The concept of cold storage may be widely known, but I'm afraid not many people know the word of controlled atmosphere storage. The modified atmosphere storage is actually the abbreviation of the modified atmosphere storage for fresh agricultural products such as fruits and vegetables. It is one of the most widely used, effective and advanced storage and preservation technologies in the world. However, due to various reasons, while the scale of controlled atmosphere storage has developed in the world, China has lagged behind. According to statistics, although there are more than 30000 fresh storage rooms for various agricultural products in China, only 5% - 7% of them use controlled atmosphere technology; In developed countries, fresh agricultural products preserved by modified atmosphere accounted for more than 80% of the total storage of edible agricultural products, while in China, it was less than 2%.

The so-called controlled atmosphere storage, also known as controlled atmosphere storage, is to increase the regulation of gas composition on the basis of cold storage. By controlling the temperature, humidity, carbon dioxide, oxygen concentration, ethylene concentration and other conditions in the storage environment, it can inhibit the respiration of fruits and vegetables, delay their metabolism process, so as to better maintain the freshness and commerciality of fruits and vegetables, and extend the storage and preservation period of fruits and vegetables. Generally, the storage period of controlled atmosphere storage is nearly twice longer than that of ordinary cold storage; The fruits and vegetables stored in the controlled atmosphere warehouse will first "wake up" from the "sleep" state after leaving the warehouse, which will extend the fresh-keeping period (sales shelf life) of fruits and vegetables after leaving the warehouse by 21 to 28 days, which is 3 to 4 times that of the ordinary cold storage. Therefore, the controlled atmosphere storage can extend the fresh-keeping period. First, its control of water loss of fresh agricultural products is particularly strict. However, the common cold storage only relies on the refrigeration system, which can not solve the problem of water loss of such products, nor can it extend the freshness period. Compared with ordinary cold storage, although the income is large, the construction cost is high. On the one hand, the high cost of the controlled atmosphere storage is an additional set of controlled atmosphere equipment; On the other hand, it is the airtight construction cost of the controlled atmosphere reservoir. Although the initial investment of the controlled gas storage is high, if it can be put into use after the completion of construction, it can bring huge economic benefits in the long run. Especially those fresh agricultural products that meet the conditions of CA storage, such as kiwi, big cherry and other agricultural products with high added value and anti-season. Facts have proved that the high investment in CA storage will inevitably result in high market returns, which is also one of the reasons for the popularity of CA storage in western countries.

To transform a common cold storage into a controlled atmosphere storage, only the following two points need to be solved: First, increase the sealing of the cold storage. Controlled atmosphere storage is to add carbon dioxide and nitrogen to the general cold storage to prolong the fresh-keeping period of fruits and vegetables. The controlled atmosphere storage requires extremely high tightness to prevent gas leakage and outdoor gas from entering. 2、 Add air conditioning equipment. The main equipment for CA preservation include carbon dioxide generator, nitrogen generator, ethylene remover, oxygen remover, etc. Fresh fruits and vegetables are a living body after being harvested. During storage, they are still carrying out normal metabolic activities dominated by respiration, which are manifested as consumption of oxygen, release of carbon dioxide, and release of a certain amount of heat. Therefore, controlling or adjusting the concentration of O2 and CO2 in the storage environment can greatly improve the storage life of some fruits and vegetables. The design purpose of the UK SST fluorescent oxygen sensor Lox-02 and carbon dioxide sensor MINIR recommended by ISweek Industrial Mining Network is to adjust the atmosphere environment of the controlled atmosphere storage by accurately measuring the concentration of oxygen and carbon dioxide, thus extending the shelf life of perishable food.