Why can’t vegetables and fruits be placed in plastic bags for a long time?

Vegetables and fruits are almost eaten every day. Most people sometimes feel that it is more troublesome to buy again and again, and they will buy a lot at home. At this time, it needs to be preserved and stored in plastic bags or environmental protection bags. It is a scientific preservation method commonly used by people. The principle is to reduce the concentration of oxygen, increase the concentration of carbon dioxide, make the fruits and vegetables in a dormant state, and prolong the storage period.

However, the storage time should not be too long. Because vegetables and fruits are organic foods, the water content is high, and the plastic bags contain water-soluble nutrients and enzymes. Fruits and vegetables are still undergoing strong breathing throughout the storage period. In general, for every 10 degrees Celsius increase, the breathing intensity doubles. Under aerobic conditions, sugars or other organic substances in fruits and vegetables are oxidatively decomposed to produce carbon dioxide and water, and a large amount of ripening is released. In the absence of oxygen, sugar can not be oxidized, only decomposes to produce alcohol, carbon dioxide, and emits a certain amount of heat.

The key point to mention here is that the concentration of carbon dioxide cannot rise indefinitely. The concentration of carbon dioxide in plastic bags or environmental protection bags should not rise by more than 10%, and the decrease of oxygen concentration should not exceed 5%. Otherwise, in order to obtain oxygen in the absence of oxygen, For the energy needed for life activities, more nutrients must be broken down.

At the same time, the alcohol produced by the lack of oxygen breathing stays in the fruit sparse, which will cause fruit rot and deterioration, so the storage time of fruits and vegetables in plastic bags or environmental protection bags should not be too long. The best way to do this is to open the mouth of the bag every two or three days, releasing carbon dioxide and heat, and then sticking the mouth, which will make the storage time of the fruits and vegetables longer.