Modified atmosphere preservation technology is an advanced scientific method applied to the storage of fruits and vegetables. It can also be used to store Chinese herbal medicines, grain and other special items that need to be stored regularly. Known by the industry as 2 1 century technology.
The difference between modified atmosphere preservation technology and general preservation technology is that the picked fruits and vegetables are still absorbing oxygen and consuming their own nutrients to survive. Once the nutrition is exhausted, fruits and vegetables begin to rot until they rot. Modified atmosphere preservation technology is to achieve the minimum oxygen content to meet the survival needs of different varieties, adjust the metabolism of fruits and vegetables, maintain the nutrition of fruits and vegetables, prolong the storage period and maintain the good quality of fruits and vegetables by adjusting the four parameters of environmental temperature, humidity, oxygen content and carbon dioxide content in the air. For example, apples can be stored for 10 weeks at constant temperature and 28 weeks in controlled atmosphere storage. Apple loses water after constant temperature storage, and the fruit becomes soft, but after controlled atmosphere storage, the difference between freshness and hardness is very obvious. Another example is chestnuts, which can be stored at constant temperature for three months and controlled atmosphere for six months. The storage period of modified atmosphere technology is about twice that of constant temperature storage. This is of great significance to the industrial economic development of fruit and vegetable products.
Second, the development trend of modified atmosphere technology
Modified atmosphere preservation technology, which was developed earlier abroad, has reached a large-scale development in the 1980s. For example, Italy has formed a modified atmosphere chain for the production, supply and sale of fruit and vegetable products, that is to say, a modified atmosphere storage warehouse is built in the place of origin, vehicles are transported by air, and a modified atmosphere turnover warehouse is sold, thus ensuring the fullness and freshness of fruit and vegetable products in the market. In order to promote the development and application of this technology, China began to introduce demonstration warehouses and warehouse-opening technologies from Japan, Germany, Australia, Poland and other countries in the 1980s, and built a number of modified atmosphere fresh-keeping warehouses. It was not popular at that time. It is very important that during the planned economy period, characteristic agriculture was not formed and advanced warehousing enterprises were not developed. In addition, the imported equipment and technology can not be combined with China's national conditions, and the investment cost of building warehouses is high. It costs 30,000 yuan to build a warehouse with imported technology, and 3 million yuan to build a new modified atmosphere warehouse with 100 tons of reserves. When stored abroad, propane or liquefied gas is used to reduce oxygen.
China began to study modified atmosphere preservation technology in the 1990s, and combined with the national conditions to carry out technology development. After repeated practice, the independent innovation technology of building warehouse was formed, which solved the key technology of closed storage of brick structure, refined the configuration of technical equipment and optimized the gas conditioning process. The advanced carbon molecular sieve physical adsorption method is used to reduce the oxygen in storage, which has no negative effect on the stored fruits and vegetables, fully meets the requirements of green food and has been patented.
Due to the establishment of a new concept of closed structure, the idea of building a warehouse is expanded, and the original brick structure building can be built or transformed into a controlled atmosphere warehouse; Can increase the controlled atmosphere function of constant temperature storage and refrigeration. The investment for the built modified atmosphere storage with reserves ranging from 10 ton to more than 500 tons is only 1/3- 1/5 of the same storage with imported technology. It has created conditions for promoting the popularization and promotion of modified atmosphere preservation technology and provided support for users to expand industrial economic development.
Third, the controlled atmosphere technology and the construction of controlled atmosphere storage have achieved initial results.
Gong Li in Qianxi, Hebei Province adopts modified atmosphere preservation technology, which can be stored for 8 months. Established a company in Harbin to distribute sugar-fried chestnuts, with a sales volume of more than 500 tons in half a year and an output value of10 million yuan, and achieved good economic benefits.
During 1997, cherry in Yantai, Shandong Province was stored by modified atmosphere technology. Foreign data show that cherries can only be stored for 1 month, but they have been stored for 45 days. When they leave the library, the fruit is green and tastes the same. The purchase price is 9 yuan /500g, and the price is 20 yuan /500g.
The storage cost of modified atmosphere technology is of great concern to everyone. 200 1 There are two warehouses in Yantai, Shandong Province, which store 7000 kilograms of peaches and 5500 kilograms of red raisins respectively. The electricity consumption of the equipment stored for one month 1000kw, and the electricity fee is 0.84 yuan /kw. After accounting, the cost per kilogram of fruit storage 1 month needs to be increased by 0.04 yuan. bale