Economic Returns from Postharvest Cured Date Palm Cultivars under Glasshouse Conditions

Traditional methods of open sun curing were used for postharvest processing of dates but, the desired quality of fruit could not be achieved due to adverse effects of dust storms and rain spells at ripening and curing stage of fruits. Covering fruit bunches with bags were also not productive and profitable; therefore, the growers switched to solar tunnel drying but couldn’t get the required results. The protocols of using solar tunnels needed fine-tuning of temperature and relative air humidity, which affect fruit quality. During dates’ drying process high temperature and low humidity is required. This research was conducted at Arid Zone Research Center, D.I. Khan, Pakistan for quick and safe ripening of date fruits under controlled conditions. For ripening of date fruits, 35 ± 5°C temperature and 80 ± 5% relative humidity; and for drying, 45 ± 5°C temperature and 30 ± 5% relative humidity levels were kept constant. The moisture contents were reduced to recommended moisture of 23-25% for shelf life stability. Data for fresh date production ranged from 39-59% of the initial value. Minimum (39%) and maximum (59%) fresh date yields were recorded in cv. Gulistan and Shakri, respectively. Similarly, minimum and maximum produce recorded in dry dates were 32 and 50% in Gol Basara and Zahidi, respectively. Maximum and minimum length observed were 5.2 cm and 2.5 cm in Dhakki and Gol Basra, respectively. Economic analysis revealed that processing of fresh dates fetched more money than dry dates for most of the popular varieties. However, Dhakki date being more preferred due to its unique taste and the highest fruit yield and the biggest fruit size; needs curing under controlled conditions.