Modified atmosphere packaging

The storability of postharvest crops is dependent on some salient factors such as moisture content, respiration rate, heat production, texture characteristics and physiological phase of ontogeny.

Among these factors, respiration rate has been recognized for decades to have an inverse relationship with storability. Crops that exhibit a relatively high respiration rate tend to deteriorate rapidly, whereas crops that respire slowly can be stored for extended periods of time. Temperature control and modification of atmosphere are two important factors in extending the shelf life of perishable food.

Modified atmosphere packaging (MAP) is a form of packaging that involves the removal of air from the pack and its replacement with a single gas or mixture.

MAP of fresh produce relies on modification of the gas composition inside the package based on the interactions between processes such as respiration of the packed product, biochemical changes and the slow permeation of gases through the container, thereby resulting in gas composition richer in CO2 and poorer in O2.

Fresh fruit and vegetables have different needs for MAP storage. In the case of ripening fruits and vegetables, modified atmosphere is used to control ripening.

In the case of plants products that are marketed in an immature form, MAP is used to retard senescence, for example, yellowing in broccoli; and in cut vegetables, such as lettuce or cabbage, modified atmosphere may be used to prevent browning of the cut surfaces.
Modified atmosphere packaging