Des pommes de meilleure qualité grâce à l'atmosphère contrôlée dynamique

La technologie de l'atmosphère modifiée dynamiques, qui permet de mettre en oeuvre des concentrations en CO2 limitées à 0,5%, est apparue au Canada il y a une dizaine d'années.
Apples are the most consumed fruit in the world, with a production 65-75 million tons worldwide, 9-11 million of which in the EU.
Controlling O2 and CO2 levels during storage made it possible to double storage life of apples.
More recently, chemical use criticized by consumers incited system designers to find alternative solutions, such as further lowering O2 levels down to around 1% (ultra low oxygen, ULO) or initial low oxygen stress ILOS, in which the fruit is momentarily placed in an atmosphere containing less than 0.5% O2 before being placed under ULO.

Dynamic Controlled Atmosphere (DCA) appeared in this context in Canada ten years ago where O2 rates are lowered to 0.5% thanks to a sophisticated system used to monitor fruit quality during the process.
Lowering O2 rates can limit fruit respiration and oxidation phenomena without provoking asphyxia. However, in DCA, fruit stress levels are monitored by checking the fluorescence of it chlorophyll, thanks to a fluorescence interactive response monitor (FIRM). Apples convert part of the light they receive into heat or fluorescence at a 690-730 nm wavelength. FIRM requires plunging the apples in darkness, before stimulating their photosystem thanks to LED lighting and then analyzing the fluorescent light emitted. This operation is renewed every two hours in order to find out if the fruit is reaching stress limits.

Around 1,000 cold stores, with over half in Italy, are currently equipped with this technology providing an overall storage capacity of 300,000 tons. It requires good-quality controlled-atmosphere systems and airtight cold stores.
Another similar technique, also relatively widespread in Italy, involves directly analyzing ethanol levels in the fruit, while additional techniques are still under development.

Conservation des pommes sous Atmosphère Contrôlée Dynamique, V. Mathieu-Hurtiger et al. Revue Générale du Froid et du Conditionnement d’Air, May 2013