Effect of Relative Humidity on Drying Kinetics of Agricultural Products

Abstract

The demand for food has been ever increasing in proportion with the growing human population. This includes agricultural products including fruits. Hence, food preservation for extended usage through drying is gaining importance. This study reports the drying behavior of several agricultural products, namely sweet potato, carrot, ginger, turmeric, passion fruit and its rind. Focus has been given to the effect of relative humidity on drying for these products at room temperature. Experiments were carried out at 27°C by varying relative humidity at 40%, 60% and 80%. It was found that the relative humidity has a strong effect on drying, with lower relative humidity providing higher drying rates. In humid surrounding like Malaysia which has an average humidity more than 70%, controlling humidity of drying air may result in an energy efficient process in comparison to raising the drying air temperature

Energy efficient drying technologies for sweet potatoes: Operating and drying mechanism, quality-related attributes

“…According to Sun et al (19), the elevated drying temperature may reduce the RH of the drying medium and increase the vapor pressure shortfall, boosting the degree of external mass transfer. Similarly, Sabudin et al (61) discovered that 40% relative humidity had the highest drying rates and moisture gradient in sweet potato drying.…”