Vegetables, especially leafy vegetables, still maintain vigorous respiration after picking, consuming oxygen, releasing carbon dioxide, moisture and heat.In view of this physiological characteristic, the core design of modern vegetable packaging boxes lies in the use of highly breathable microporous film technology, supplemented by a humidity control mechanism, in order to create a suitable microenvironment to extend the shelf life.Highly breathable microporous films are usually formed by laser punching on plastic films (such as PE and PP) or using special additives to form micron-level channels.The pore size and density of these micropores have been accurately calculated to achieve a high water vapor transmittance (MVTR), allowing the water vapor produced by leafy vegetable respiration to escape in time to prevent oversaturation of humidity in the package; at the same time, maintain a moderate exchange of oxygen and carbon dioxide to avoid fermentation deterioration caused by anaerobic respiration or physiological damage caused by excessive carbon dioxide concentration.

Humidity regulation is another key technology.Simple high air permeability may cause vegetables to lose water and wilt in a dry environment, so functional lining materials need to be used in combination.The most common is to place a food-grade moisture-absorbing pad at the bottom of the box.This kind of mat is made of a combination of super absorbent resin (SAP) and pulp. It can effectively absorb the condensate released by the vegetables themselves and the juice oozing from the incision, so that the vegetables are isolated from liquid water and prevent decay caused by water stains.At the same time, it acts as a buffer library, which can slowly release part of the moisture when the environment dries out, and maintain the stability of the relative humidity in the package.In addition, the reasonable top gap space reserved in the package also provides the necessary volume for moisture diffusion and balance.

In actual warehousing and logistics, the effectiveness of this technology combination is highly dependent on the synergy of the cold chain.Low temperature (usually 0-4℃) can significantly reduce the respiration rate of vegetables and reduce the generation of water vapor and heat from the source.Therefore, an ideal vegetable preservation solution is: the cold chain provides a basic low temperature environment, the highly breathable packaging maintains gas balance, and the moisture-absorbing pad manages liquid moisture.When companies choose vegetable boxes, they should require suppliers to provide moisture permeability data and moisture absorption pad performance reports for specific vegetable varieties (such as spinach, lettuce, and coriander), and verify their comprehensive preservation effect through simulated shelf life tests, so as to ensure that vegetables can maintain their tender texture and emerald green appearance to the maximum extent during the long journey from the origin to the shelf.