Storage of Dates Under Carbon Dioxide Atmosphere for Quality Preservation
S. NAVARRO*, J.E. DONAHAYE, MIRIAM RINDNER AND A. AZRIELI
Dept. of Stored Products, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel [*e-mail: vtshlo@netvision.net.il]
Abstract: Dates grown in Israel served as a model to demonstrate the feasibility of storing dried fruit under CO₂ atmosphere. A controlled atmosphere of 60-80% CO₂ was used within a 151 m³ plastic chamber partially filled with 30 tonnes of dates stacked in crates on pallets. The dates were stored in the chamber in bulk (in boxes of 10 kg or crates of 400 kg on pallets) or packed (250 g capped plastic cups) on pallets containing dates of vars. 'Hallawi', 'Hadrawi', 'Zahidi', 'Derei' and 'Ameri'. Dates were sampled before closing the chamber, after one month and after 4.5 months at the end of storage. The following were investigated: presence of insects and molds; skin sloughing; sugar formation; water activity (aw); and color changes (only on var. Zahidi). At the initial purge phase the desired CO₂ concentration was obtained in the chamber within one hour by introducing the gas under high pressure. An intermittent maintenance phase was then applied for 4.5 months using approximately 0.8 kg CO₂ per day. At the end of storage, quality of the treated dates was compared to controls stored at -18°C. No significant difference was found between the treated dates and controls. The insect population was effectively controlled. This technology is proposed for the treatment of stored dates to control pests and maintain quality.
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