Quality Characteristics of ‘Zaghloul’ Date Fruits During Cold Storage as Affected by Postharvest Irradiated Chitosan Treatments
The potential of chitosan (irradiated and unirradiated) in preserving bisir Zaghloul date fruits during cold storage was investigated. Solid chitosan powder was gamma irradiated with 25 and 50 kGy doses, chitosan solutions were prepared and fruits were treated prior to cold storage. Initial fruit quality characteristics were assessed before refrigeration at 0 ± 1°C and RH 85- 90 % for up to 42 days, during which physiochemical characteristics were determined periodically, every 14 days. Different treatments were applied by immersion in one of the following for two minutes with temperatures adjusted to 45°C: Control (water); 0.5%, unirradiated chitosan; 0.5 %, 25 kGy irradiated chitosan; 0.5%, 50 kGy irradiated chitosan; 1.0 %, unirradiated chitosan; 1.0 %, 25 kGy irradiated chitosan; 1.0 %, 50 kGy irradiated chitosan, solutions. Chitosan generally decreased weight loss and decay and increased rutab percentages and controlled increases in total soluble solids and total sugars and decreases in fruit firmness and titratable acidity. As for the effect of radiation applied to chitosan, it generally reduced rutab % compared to control and limited chitosan’s efficiency in controlling respiration rate, weight loss, firmness loss and acidity decrements.