Refrigeration for preservation of the Moroccan date: Situation and physical analysis of the quality
The production of date palm in Morocco, estimated at around one hundred thousand tons per year, contributes to the generation of income, 40 to 60 %, for nearly 2 million of the oasis population. However, this date palm production is exposed to constraints related to good harvesting practices, post-harvest treatments, conservation and storage. This study consists of a diagnosis (based on surveys) of date processing and storage conditions in five cold storage units located in the oases of South-East of Morocco. These surveys were supplemented by monitoring the quality and dehydration rate of two main varieties of date-palm fruits: Majhoul and Boufeggous. Survey results showed that the storage capacity of the majority of cold storage units is about 400 tons. The date-palm fruits are processed in several stages; the most important of which are fumigation with phosphine (PH3) for 3 to 5 days at room temperature and manual sorting of dates into three categories according to their size and the presence of defects. After these treatments, all varieties of dates are stored in the same cold room at a temperature of 0 to 4°C for a period of 1 to 10 months. The storage rooms are not equipped with humidifiers which do not allow a control of the relative humidity. The major defects observed during storage are the appearance of glucose spots inside the fruit epidermis (57 % on average) and the detachment of the date-palm fruit wall (20 % on average). The kinetics of dehydration showed a similarity between the varieties with a respective average of 6.5 % for the Majhoul and 7 % for Boufeggous, after 12 months of storage.
Key-Words: Morocco, date, cold storage, quality, dehydration.