Influence of film wrapping on quality maintenance of "Salustiana" oranges held in shelf-life conditions

"Salustiana" oranges were dipped in a 500 mg/L imazalil emulsion and wrapped in polystyrene trays using three different plastic films: Omni, MR and MY, with high, medium and low permeability to gases and water vapour, respectively. Fruits were then stored at ambient temperature (18°-20°C) and relative humidity (60-65%) for 6 weeks. MY film created in-package anaerobic conditions (about 10% CO2and 8% 02, increased the rate of deterioration of internal quality parameters and promoted pathogen development, even in fruits treated with imazalil (28% decayed fruits after 6 weeks). Omni film did not alter the nutritional composition, but had little influence in reducing the transpiration rate as fruits at the end of storage lost about 14% weight, compared to 18% for non-wrapped fruits and 2% for those wrapped with the other two films. Very positive results were obtained with the imazalil-MR film combination, which let the fruits maintain their initial chemical and aesthetical characteristics during the entire storage time and limited loss due to decay to about 1%.