Refractance window drying: A cohort review on quality characteristics

Background: The most commonly used conventional drying techniques causes several nutritional, physical and chemical changes which makes food unacceptable to the consumer. The increase in demand of higher retention of nutrients and physico-chemical characteristics of food products requires the development of novel drying technique. Refractance WindowTM (RWTM) drying has huge potential to cause minimal changes in the quality properties of food. RWTM drying uses circulating hot water to bring thermal energy to the material to be dried. Scope and approach: To understand the potential opportunities of RWTM drying in food applications, it is very essential to examine it?s effect on different quality characteristics. The present review article summarizes the working principle and the effect of RWTM drying on the retention of bioactive compounds and physicochemical properties of food products. Key findings and conclusions: In RWTM drying, the evaporative cooling at the surface of the drying material restricts the temperature of 70 and 85 ?C. At this reduced temperature material quality and heat sensitive nutritional compounds can be highly retained in the final dried product. This characteristic of RWTM drying extends its applications for high value food products. Comparison of RWTM drying with other drying process confirms that it provides more advantageous in terms of retention of heat labile compounds, retention of quality parameters and energy efficiency with reduced operating cost.