EFFECT OF TEMPERATURE AND MODIFIED ATMOSPHERE ON QUALITY PRESERVATION OF SAYER DATE FRUITS (PHOENIX DACTYLIFERA L.)

Sayer date fruits were stored by different preservation techniques including high carbon dioxide modified atmosphere packaging (MAP), cool storage and freezing for 150 days. The effects of these treatments on several quality factors of the fruits were investigated. Control package samples (kept at 30C without atmosphere modification) had the highest number of live insects as well as yeast and mold colony counts (P < 0.05). pH values of the MAP samples stored at 30C were less than the other treatments. Water activity was reduced during the storage in all the samples. Fruit blemishing in the high CO₂ MAP samples was similar to that of the controls. However, the least blemishing was at-18C. The MAP containing 85% CO₂ + 3% O₂ + 12% N₂ and 75% CO₂ + 12% O₂ were chosen as the best methods of preservation and quality maintenance of sayer dates with limited effects on the appearance of physiological disorder signs. The effect of different preservation techniques (high CO₂ modified atmosphere packaging [MPA], cool storage and freezing) on insect elimination and quality of sayer date fruits was investigated. As no off-odor or off-flavor due to anaerobiosis was reported during the experiments, sayer dates were considered to be resistant to high CO₂ concentration or low oxygen probably due to their low respiration rate. Both MPA containing 85% CO₂ and freezing eliminated insects, inhibited mold growth, reduced sugar accumulation and produced negligible blemishing and pH reduction, and therefore were considered appropriate for preservation of sayer dates.