Optimization of Vacuum Drying Characteristics of Date Powder

Abstract

Kabkab, Khazravi, and Zark are three varieties of Iranian dates representing high, middle, and low sugar content, respectively. Under the vacuum conditions, powders from these dates were produced and placed in the optimized state for the dehydration reaction. The statistical analyses showed that the moisture reduction range of these three varieties at various conditions (100°C and 15.3 cm Hg, 93°C and 30.4 cm Hg, 84°C and 54.6 cm Hg, 68°C and 60.1 cm Hg) were 17.27±0.16, 20.89±0.19, and 7.61±0.02%, respectively. The analysis of variance (ANOVA) on date variety and thickness (0.2, 1, 2, 2.5, and 3 cm) in drying time indicated that the Zark variety with low moisture and sugar contents exhibited the lowest drying time (about 6 h), followed by Khazravi and KabKab. The optimum condition (85°C, 54.6 cm Hg, and 1 cm thickness during 7 h of drying time) was selected for its favorable effects on the moisture reduction, smell/color quality, energy usage, and economical feasibility.

Keywords:

• Date variety
• Date powder
• Dehydration
• Moisture reduction
• Process condition

Notes

^a Standard deviation.

^b (g/100 g fresh weight).

^c (g/100 g dry weight).

^d (mg/100 g dry weight).

^a Standard deviation.

^a Significantly different (P < 0.01).

^a Standard deviation.