Chilling and Freezing Storage for Keeping Overall Quality of “Deglet Nour” Dates

The effect of storage at 0 and 20°C for 30 days with and without a passive Modified Atmosphere Packaging (MAP) and the effect of a freezing storage at -20, -40 and -80°C for 10 months followed by 1 week at 5°C on overall quality of Deglet Nour dates were studied. After the storage time, the physicochemical properties and sensory quality, microbial development, and moth infestation (Ectomyelois ceratoniae) of dates were monitored. It was observed that the storage temperature greatly affected the overall quality of dates. The 0°C was recommended for a short-term storage of fresh dates of one month. The MAP technique (6 kPa O2+12 kPa CO2) showed a positive effect on keeping overall quality of dates at 20ºC. However, for a long-term storage (10 months in frozen conditions plus 1 week at 5ºC), all freezing temperatures assayed kept the overall quality of dates and no differences were observed among them. In order to minimize the global costs, -20°C was considered as the most adequate temperature for a long-term freezing storage period. In conclusion, these chilling and freezing techniques could be recommended for commercial use at industrial scale.