Comparison of drying kinetics and product quality from convective heat pump and solar drying of Roselle calyx

This study investigated the effect of temperature (40, 50, and 60 °C) and sample mass (100, 200, and 300 g) on the drying characteristics and product quality of Roselle calyx using heat pump dryer. It was observed that higher drying temperature and lower sample mass led to a shorter drying time (faster drying rate). Higher temperature supplied more heat to the Roselle sample, which increased the activity of water molecules and moisture...