Refractance Window (RW) drying has recently attracted considerable attention in both academic and industrial circles. This study aimed to evaluate how RW drying affects the quality of guava powder compared to traditional hot air (HA) drying methods, especially for materials that are challenging to dry using conventional techniques. Key aspects of the investigation included analyzing drying kinetics and assessing quality attributes such as rehydration ratio, water activity, solubility, hygroscopicity, bulk density, color values, L-ascorbic acid, total phenolic compounds, total flavonoids, and DPPH radical scavenging activity.
The findings revealed that RW drying significantly reduced drying time and improved drying efficiency compared to HA drying. Specifically, the drying times for RW at temperatures of 50, 60, and 70°C were 60, 25, and 15 minutes, respectively. Additionally, the cost of producing one kilogram of guava powder was lower with RW drying—5.83, 8.01, and 11.65 for temperatures of 50, 60, and 70°C, respectively—compared to HA drying.
Moreover, RW drying resulted in higher values for rehydration ratio, bulk density, solubility, and hygroscopicity than those achieved with HA drying at 60°C over 480 minutes. RW drying also demonstrated a notable retention of antioxidant compounds, including L-ascorbic acid, total flavonoids, and DPPH radical scavenging