Some engineering factors affecting referactance window drying of guava

Document Type : Original Article

Authors

Department of Agricultural Products Process Engineering, Faculty of Agricultural Engineering, Al-Azhar University, Cairo, Egypt.

Abstract

In the present work drying kinetics of Guava of initial moisture content 88 ±1 % w.b. using Refractance Window (RW) dryer as affected by three different levels of water basin temperature, namely: 80, 85 and 90 ±1°C and three different puree thickness of approximately 1,2 and 3mm as a parameter. The indicators that used to evaluate this system such as rehydration ratio, color as quality indicators, productivity(kg/h), drying efficiency and costs. The main results showed that drying time was affected by water basin temperatures and puree thickness significantly, the drying time decreases with water basin temperature increases and puree thickness decreases. The puree temperature affected by drying elapsed time and the rehydration ratios increased as water basin temperature decreases. The RW drying method had significant impact on color quality of dried samples. Increasing puree thicknesses, productivity decreases due to its dependence on drying time. The drying efficiencies were ranged from 28 to 65%. Moderate values of drying costs were recorded at 85°C and 2mm thickness.

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