Use of passive and active modified atmosphere packaging to prolong the postharvest life of three varieties of apricot (Prunus armeniaca, L.)

The evolution of the atmospheric composition (O-2 and CO2 and ethylene) passively produced by three varieties of apricots (Beliana, Rouge de Rousillon and Polonais) stored at 10 degrees C under four plastic films of different permeabilities was studied. The results corresponding to respiratory intensity (IR) revealed that, while the IR decreased during the storage period under modified-atmosphere packaging, it increased again with the opening of the bags and the exposure of the fruits to air. The modified atmosphere inside the bags (O-2 and CO2) and the time necessary to reach equilibrium depended on the IR of the fruits and the permeability of the film. The ethylene concentration decreased from the second day onwards in all the cases studied; this decrease being more pronounced in the films of least permeability due to a combination of its diffusion through the film and the inhibition of its synthesis as the CO, concentration increased and O-2 concentration decreased. Partial deviations in the metabolism of the three varieties were detected in the two films of lowest permeability (6060 and 12100 cm(3) of O-2 and CO2 m(-2)/24 h(-1) atm(-1) at 25 degrees C) due to anoxia. The use of the active modified atmosphere, replacing the initial atmosphere of the bags with an atmosphere enriched with CO2 (20% CO2 and 80% air), did not modify the gas composition at equilibrium, although it shortened the time necessary for it to be reached. For the Beliana variety a slight decrease in ethylene concentration was observed inside the bags with an active modified atmosphere in relation to that of the bags with a passive modified atmosphere. The accumulation of ethanol in the tissues was not higher under the active modified atmosphere than under the passive modified atmosphere.