Effects of Zero Energy Evaporative Cooling Pads on the White Sapote (Casimiroa edulis L.) Fruit Quality and Storage Life

White sapote fruit is one of the underutilized crops in Ethiopia, with a high postharvest loss magnitude (30-70%). Zero energy cooling chamber (ZECC) performance was evaluated with this fruit. The chamber was constructed from locally available materials in a hot and arid area, Dire Dawa. The experiment evaluated the cooling efficiency of ZECC with different cooling pads (sawdust, charcoal, and sand) in CRD with three replications. The cooling efficiency of ZECC was evaluated before and after loading for six weeks. Seventy-five litres of water (25 L for each ZECC) was used thrice daily to keep the cooling pads wet. The environmental air condition of the storage area varied between 24.5 and 32°C, and the average relative humidity (RH) was 47.59%. ZECC storage with different porous materials reduced the temperature by 6.0-10.2°C and raised the RH to 88.2, 85.1, and 87.6% for the cooling pads of sand, sawdust, and charcoal, respectively. Cooling efficiencies of pads resulted in 91.22, 87.95, and 87.82%, respectively, for sand, sawdust, and charcoal with no significant difference. Physiological weight loss of fruit stored in ZECC was 17% on day 18, whereas a similar loss was recorded for control by the 12th day. The shelf life of the fruits was very much prolonged, as expressed in terms of various quality attributes. Hence, smallholder farmers can use ZECC to extend the storage life of fruits in arid and semiarid areas.