Refractance Window Dryer (RWD) for Food Products Using Solar Powered System: A Review

Abstract

Traditional food drying approach caused significant nutritional, physical and chemical changes in the dried products, which caused less appetizing. As the market for foods with preserved nutrients and physicochemical properties grows, new drying processes are needed. Refractive window drying (RWD) technology has proven to be an effective method to minimize negative effects on food quality. RWD circulates hot water to generate heat energy during the drying process. In this process, surface evaporative cooling limits the temperature of the dry material to a range of 70°C to 85°C. This limited temperature range allows for preserving heat-sensitive food ingredients and maintaining material quality. RW drying's unique properties make it ideal for processing high-quality food products. This review study investigates the effects of RW drying on various quality attributes to explore potential applications in the food industry. This article reviews the operating philosophy of RWD and explains how it affects the retention and physicochemical properties of bioactive components in foods. Additionally, RW drying offers advantages over traditional drying methods, including improved retention of thermally labile compounds, compliance with quality standards, and increased energy efficiency due to reduced operating costs. This study focuses on the use of solar energy as an auxiliary heat source and also evaluates the effectiveness of his RWD using a solar auxiliary heating system for drying food. The system harnesses solar energy to increase energy efficiency and reduce dependence on traditional energy sources. The performance evaluation results provide important new information regarding the efficiency and long-term viability of combining RWD and solar-assisted heating systems in food drying processes.