The importance of the storage of tropical fruits under modified atmosphere : Application to mango

The principle of storage under modified atmosphere (that is to say that differs from the normal composition of the ambient air) is based on the one hand on knowledge of the respiratory physiology of the produce to be packed and on the other on knowledge of the packing material itself (structure, composition and permeability). This modification of the atmosphere surrounding produce can be achieved either by using a selective or micro-perforated plastic film or by applying a coating whose properties must be equivalent to those expected of a packaging film (greater or lesser permeability to oxygen, carbon dioxide and ethylene). Modified atmospheres are used to slow the different evolution metabolisms of fruits, whether this involves the respiratory metabolism or the different biochemical reactions that take place during maturation. For the moment, these techniques can only be envisaged in combination with chilling and confer a considerable advantage in comparison with cold alone. Indeed, there is a trend to subject produce to temperatures that are much too low-often through wishing to optimise and ensure the effect of cold-causing chilling injury (tropical produce is particularly susceptible to this); the addition of a film or coating can reduce fruit susceptibility to low temperatures. Furthermore, it reduces fruit weight loss (by limiting desiccation) during transport and storage. Research at Cirad-flhor is focused on the testing of films and coatings in order to reply to the questions raised; its final objective is to enable the sea transport of practically ripe fruits. The positive results obtained are being validated at the commercial scale for a pre-selected type of coating. The presentation of some results for mango, with discussion of the advantages and disadvantages connected with the choice of film or coating. (Résumé d'auteur