Paper Title
Atmospheric Superheated Steam Drying of Sweet Potato

Abstract
The aim of this research is to studythe use of superheated steam drying for sweet potatounder atmospheric condition. The effects of drying conditions, i.e., steam temperature and velocity on drying kinetics and product quality viz. color, shrinkage and texture (hardness and toughness)were investigated.The experiments were conducted atsteam temperatures of 120 - 180°C and velocities of 2m/sand5 m/s under atmospheric pressure. Sweet potato with initial moisture content ofabout74.9% wet-basis was dried until its moisture content reached approximately18% wet-basis. Results showed that drying rateincreased as steam temperature and velocity increased.Newton’s equation was used to describe the drying kinetics of sweet potato, in which its drying constant was expressed as a function of drying conditions. Total color difference tended toincrease as steam temperature increased whereas it seemed to increase asvelocityincreased.Shrinkage,hardnessand toughness decreased assteamvelocity increased whileincreasing steam temperature reduced shrinkage,hardness (only in the range of 120oC - 160oC) and toughness.Consideringboth product quality and drying time, superheated steam drying at 140°C and 5 m/sandat 160°C and 2 m/sare the suitable conditions for drying sweet potato in this research. Keywords - Drying, Superheated Steam, Sweet Potato, Quality.